9 Radio Link Control (RLC) procedures in packet transfer mode

3GPP44.060General Packet Radio Service (GPRS)Mobile Station (MS) - Base Station System (BSS) interfaceRadio Link Control / Medium Access Control (RLC/MAC) protocolRelease 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

9.0 General

The RLC function is responsible for:

– Interface primitives allowing the transfer of upper layer PDUs between the upper layer and the MAC function;

– Segmentation of upper layer PDUs into RLC data blocks and re-assembly of RLC data blocks into upper layer PDUs;

– Segmentation of RLC/MAC control messages into RLC/MAC control blocks and re-assembly of RLC/MAC control messages from RLC/MAC control blocks;

– Backward Error Correction (BEC) procedures enabling the selective retransmission of RLC data blocks.

In this clause Packet Ack/Nack refers to any of the following messages or field:

– PACKET DOWNLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK TYPE 2, EGPRS PACKET DOWNLINK ACK/NACK TYPE 3, EGPRS PACKET DOWNLINK ACK/NACK DLMC, MBMS DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK HIGHER CC;

– PACKET UPLINK ACK/NACK, EC PACKET UPLINK ACK/NACK or EC PACKET UPLINK ACK/NACK AND CONTENTION RESOLUTION;

– PAN.

Additionally the following definitions apply:

– Sequence Number Space (SNS):

– 128 in GPRS,

– 2048 in EGPRS,

– 2048 or 8192 in DLMC configuration (see sub-clause 5.13),

– 32 in EC-GSM-IoT;

– Window Size (WS):

– GPRS: 64

– EGPRS: 64 to 1024

– DLMC configuration (EGPRS): determined by the buffer size supported by a mobile station (see Table 9.1.9.3.2)

– EC-GSM-IoT: 16.

A mobile station that supports multiple TBF procedures can operate multiple RLC entities simultaneously each one with its’ own set of RLC parameters (e.g. sequence number; receive and transmit windows etc.).

If a mobile station in a DLMC configuration using a SNS of 8192 is reconfigured so that it leaves DLMC configuration while the downlink TBF remains assigned, it shall continue using a SNS of 8192. A mobile station that supports DLMC configuration and has a downlink TBF with a single downlink carrier assigned (i.e. it is not in a DLMC configuration) shall immediately begin using a SNS of 8192 if the maximum number of downlink timeslots it supports (see 3GPP TS 24.008) is greater than 20 and either of the following occurs:

– It receives an assignment message that causes it to enter DLMC configuration, the assignment message indicates an SNS of 8192 shall be used, and it is not already using a SNS of 8192.

– It experiences PS Handover to a DLMC configuration and the PS HANDOVER COMMAND message indicates an SNS of 8192 shall be used.

Only RLC acknowledged mode is supported in EC TBF mode.

9.1 Procedures and parameters for peer-to-peer operation

A TBF is comprised of two peer entities, which are the RLC endpoints. In case of EMST, a TBF is comprised of one, two or three pairs of peer RLC entities, which are the RLC endpoints. Each RLC endpoint has a receiver that receives RLC/MAC blocks. Each RLC endpoint also has a transmitter that transmits RLC/MAC blocks.

An MBMS bearer is comprised of one transmitting RLC endpoint at the network side and several receiving RLC endpoints, one for each mobile station involved in the p-t-m transmission. The transmitting RLC endpoint transmits RLC/MAC data and control blocks and may receive only RLC/MAC control blocks. Each receiving RLC endpoint receives RLC/MAC data and control blocks and may transmit only RLC/MAC control blocks, upon polling. An MBMS bearer operates in RLC non-persistent mode (see also sub-clause 9.3.4).

Each endpoint’s receiver has a receive window of size WS (see sub-clause 9.1.9).

In RLC acknowledged mode, the receive window is defined by the receive window state variable V(Q) in the following inequality[ V(Q) £ BSN < V(Q)+ WS ] modulo SNS (for the method of interpreting inequalities in this format refer to sub-clause 9.1.8). All BSNs which meet that criteria are valid within the receive window.

In RLC unacknowledged mode, all values of BSN are within the receive window.

In RLC non-persistent mode, the receive window is determined after recalculating the receive state variable V(R) (as described in sub-clause 9.1.5) and the corresponding receive window state variable V(Q) (as described in sub-clause 9.1.6.4). All BSNs which meet the following inequality [ V(Q) £ BSN £ V(R)] modulo SNS are valid within the receive window.

An RLC data block is considered received, when it is received in a layer 1 frame with consistent parity bits (in EGPRS TBF mode: header and relevant data parity bits) and correctly addresses the receiving RLC endpoint.

Each endpoint’s transmitter has a transmit window of size WS. In RLC acknowledged mode and in RLC non-persistent mode, the transmit window is defined by the send state variable V(S) in the following inequality: [ V(A) £ BSN < V(S) ] modulo SNS, where [ V(S) – V(A) ] modulo SNS £ WS. All BSNs which meet that criteria are valid within the transmit window. In RLC unacknowledged mode, all values of BSN are within the transmit window.

In RLC non-persistent mode, if the NPM Transfer Time limitation is used then the network shall not change the NPM Transfer Time value. The mobile station shall ignore any NPM Transfer Time different from what is currently being used. If EMSR is enabled for an RLC entity operating in RLC Non-persistent mode then an independent NPM Transfer Time limitation may be assigned for each PFC assigned a unique TFI.

9.1.1 Send state variable V(S)

Each RLC endpoint transmitter shall have an associated send state variable V(S). V(S) denotes the sequence number of the next in‑sequence RLC data block to be transmitted. V(S) can take on the value 0 through SNS – 1. V(S) shall be set to the value 0 at the beginning of each TBF in which the RLC endpoint is the transmitter. The value of V(S) shall be incremented by 1 after transmission of the RLC data block with BSN = V(S). In RLC acknowledged mode, V(S) shall not exceed V(A) modulo SNS by more than the maximum allowed number of outstanding RLC data blocks WS. In RLC non-persistent mode, V(S) may be incremented independently on the value of V(A). When EMSR is enabled, a single send state variable V(S) is maintained regardless of how many PFCs share a given RLC entity.

9.1.1a Control send state variable V(CS)

The network RLC endpoint transmitter shall have one instance of an associated control send state variable V(CS) for each parallel control transaction identified by the RTI field of the RLC/MAC control block header. V(CS) denotes the sequence number of the next in-sequence RLC/MAC control block to be transmitted for the control transaction. V(CS) can take on the values 0 or 1 when RLC/MAC control message segmentation into two RLC/MAC control blocks is used, and the values 0 to 8 when extended RLC/MAC control message segmentation is used (see sub-clause 9.1.12a). V(CS) shall be set to the value 0 prior to the transmission of each RLC/MAC control block that contains the first octet of an RLC/MAC control message of the control transaction and the value of V(CS) shall be set to 1 after the transmission of the RLC/MAC control block with RBSN = 0. The value of V(CS) shall then be incremented by 1, when extended RLC/MAC control message segmentation is used, after the transmission of the next in-sequence RLC/MAC control block and so on.

9.1.2 Acknowledge state variable V(A)

In RLC acknowledged mode, each RLC endpoint transmitter shall have an associated acknowledge state variable V(A). V(A) contains the BSN value of the oldest RLC data block that has not been positively acknowledged by its peer. V(A) can take on the values 0 through SNS – 1. V(A) shall be set to the value 0 at the beginning of each TBF in which the RLC endpoint is the transmitter. The value of V(A) shall be updated from the values received from its peer in the received block bitmap (RBB) of the PACKET UPLINK ACK/NACK message, the EC PACKET UPLINK ACK/NACK message, the EC PACKET UPLINK ACK/NACK AND CONTENTION RESOLUTION message, the EGPRS PACKET DOWNLINK ACK/NACK message, the EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message, the EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message, the EGPRS PACKET DOWNLINK ACK/NACK DLMC message or the EC PACKET DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK HIGHER CC message (see sub-clause 9.1.8)

Furthermore, [ V(S) – V(A) ] modulo SNS £ WS.

In RLC non-persistent mode, each RLC endpoint transmitter shall have an associated acknowledge state variable V(A). V(A) contains the BSN value of the oldest RLC data block that has not yet been positively acknowledged by the corresponding peer or peers and whose BSN satisfies the inequality [ V(S) – BSN ] modulo SNS £ WS. V(A) can take on the values 0 through SNS – 1. V(A) shall be set to the value 0 at the beginning of each MBMS bearer or EGPRS TBF for which the RLC endpoint is the transmitter.

– When RLC non-persistent mode is used for an MBMS bearer the value of V(A) shall be updated from the values received from its peers in the received block bitmap (RBB) of the MBMS DOWNLINK ACK/NACK message (see sub-clause 9.1.8).

– When RLC non-persistent mode is used for an EGPRS TBF the value of V(A) shall be updated from the values received from its peer in the PACKET UPLINK ACK/NACK message, the EGPRS PACKET DOWNLINK ACK/NACK message, the EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message, the EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message, the EGPRS PACKET DOWNLINK ACK/NACK DLMC message or the PAN field.

– V(A) shall be set to BSN’, where BSN’ is the BSN value of the oldest RLC data block not yet positively acknowledged by the corresponding peer or peers which meets the condition [V(S) – BSN’] modulo SNS  WS, or it shall be set to V(S) if all RLC data blocks have been positively acknowledged by the corresponding peer or peers.

9.1.3 Acknowledge state array V(B)

9.1.3.1 Acknowledge state array V(B) for GPRS TBF Mode

In RLC acknowledged mode, each RLC endpoint transmitter shall have an associated acknowledge state array (V(B)). V(B) is an array of SNS elements indicating the acknowledgement status of WS previous RLC data blocks. The array is indexed relative to the acknowledge state variable V(A) modulo SNS. The values of V(B) shall be updated from the values received from its peer in the received block bitmap (RBB) of the Packet Ack/Nack message (see sub-clause 9.1.8)

If V(S) = V(A) + WS modulo SNS (i.e. the transmit window is stalled), the sending side shall transmit the oldest RLC data block whose corresponding element in V(B) has the value PENDING_ACK, then the next oldest RLC data block whose corresponding element in V(B) has the value PENDING_ACK, etc. If all RLC data blocks whose corresponding element in V(B) has the value PENDING_ACK has been transmitted once, the process shall be repeated beginning with the oldest RLC data block. This process of transmitting the oldest RLC data blocks whose value in V(B) has the value PENDING_ACK shall continue, as long as equation [V(S)=V(A)+WS] modulo SNS holds.

When an element in V(B) falls outside of the active transmit window, i.e. [ V(A) £ BSN < V(S) ] modulo SNS, the element shall be set to the value INVALID.

In the extended uplink TBF mode, if V(S) = V(A) and there is no RLC data block with BSN = V(S) available, the mobile station shall stop sending RLC data blocks. The mobile station shall continue sending RLC data blocks when a RLC data block with BSN = V(S) is available.

9.1.3.2 Acknowledge State Array V(B) for EGPRS TBF Mode

9.1.3.2.1 EGPRS TBF running in RLC acknowledged mode

In RLC acknowledged mode, each RLC endpoint transmitter shall have an associated acknowledge state array (V(B)). V(B) is an array of SNS elements indicating the acknowledgement status of WS previous RLC data blocks. The array is indexed relative to the acknowledge state variable V(A) modulo SNS. The values of V(B) shall be updated from the values received from its peer in the reported bitmap (RB) of the Packet Ack/Nack message (see sub-clause 9.1.8). If a compressed reported bitmap is received, decompression shall be first applied according to sub-clause 9.1.10.

The transmitter shall transmit the oldest RLC data block whose corresponding element in V(B) indexed relative to V(A) has the value NACKED. As each RLC data block is transmitted the corresponding element in V(B) is set to the value PENDING_ACK. If the RLC data block to be transmitted is split over two radio blocks, both radio blocks shall be transmitted. As an exception, if the transmitter supports DTR, [ V(S) < V(A) + WS ] modulo SNS and the RLC data block with BSN = V(S) is available, the transmitter may transmit the RLC data block with BSN = V(S) instead of the oldest RLC data block whose corresponding element in V(B) has the value NACKED.

NOTE: This exception should only be used to avoid a mobile station entering DTR mode or the network believing that a mobile station may have entered DTR mode (see sub-clause 8.1.8.2) when the transmitter has received new data from the upper layers.

If [ V(S) < V(A) + WS ] modulo SNS and no RLC data blocks have a corresponding element in V(B) with the value NACKED, the RLC data block with BSN = V(S) shall be transmitted and the corresponding element in V(B) shall be set to the value PENDING_ACK. If the transmitter is the mobile station, the pre-emptive transmission bit is set to ‘1’ in the PACKET UPLINK ACK/NACK message and there are no further RLC data blocks available for transmission (i.e. the RLC data block with BSN= V(S) does not exist), the sending side shall retransmit the oldest RLC data block whose corresponding element in V(B) has the value PENDING_ACK, then the next oldest block whose corresponding element in V(B) has the value PENDING_ACK, etc. If in this case there are no RLC data blocks whose corresponding element in V(B) has the value PENDING_ACK and either the uplink TBF is not operated in extended uplink TBF mode or the uplink TBF is operated in extended uplink TBF mode but the mobile station shall not refrain from sending an RLC/MAC block (i.e. EXT_UTBF_NODATA is set to ‘0’), the sending side shall retransmit the oldest RLC data block whose corresponding element in V(B) has the value TENTATIVE_ACK, then the next oldest block whose corresponding element in V(B) has the value TENTATIVE_ACK, etc. This entire procedure shall be repeated, starting with the oldest RLC data block whose corresponding element in V(B) has the value PENDING_ACK or has the value TENTATIVE_ACK if no element has the value PENDING_ACK, for as long as the applicable conditions for pre-emptive retransmission are true.

If [V(S) = V(A) + WS] modulo SNS (i.e. the transmit window is stalled), the sending side shall transmit the oldest RLC data block whose corresponding element in V(B) has the value PENDING_ACK, then the next oldest RLC data block whose corresponding element in V(B) has the value PENDING_ACK, etc. If in this case there are no RLC data blocks whose corresponding element in V(B) has the value PENDING_ACK and either the uplink TBF is not operated in extended uplink TBF mode or the uplink TBF is operated in extended uplink TBF mode but the mobile station shall not refrain from sending an RLC/MAC block (i.e. EXT_UTBF_NODATA is set to ‘0’), the sending side shall retransmit the oldest RLC data block whose corresponding element in V(B) has the value TENTATIVE_ACK, then the next oldest block whose corresponding element in V(B) has the value TENTATIVE_ACK, etc. This process of retransmitting RLC data blocks whose value in V(B) has the value PENDING_ACK (or TENTATIVE_ACK) shall be repeated, starting with the oldest RLC data block whose corresponding element in V(B) has the value PENDING_ACK or has the value TENTATIVE_ACK if no element of V(B) has the value PENDING_ACK, as long as equation [V(S)=V(A)+WS]modulo SNS holds. If the transmitter is the mobile station and the pre-emptive transmission bit is set to ‘0’ in the PACKET UPLINK ACK/NACK message the transmitter shall not retransmit RLC data blocks whose corresponding element in V(B) has the value PENDING_ACK or TENTATIVE_ACK. When a PACKET UPLINK ACK/NACK message or a PAN field is received the mobile station shall retransmit the RLC blocks which are set to NACKED in V(B) and new RLC data blocks as far as the transmit window (if advanced) allows. However if the RLC data block is the last in the TBF it shall be retransmitted even if its state is PENDING_ACK or TENTATIVE_ACK. The default for the mobile side is that the transmitter shall use pre-emptive retransmission. If the transmitter is on the network side this process (pre-emptive retransmission) of retransmitting the oldest RLC data blocks whose value in V(B) has the value PENDING_ACK or TENTATIVE_ACK is optional.

NOTE: If the Mobile Station only has RLC data blocks whose value in V(B) has the value PENDING_ACK or TENTATIVE_ACK and the pre-emptive transmission bit is set to ‘0’, the rules defined in sub-clause 8.1.1 apply (i.e. PACKET UPLINK DUMMY CONTROL BLOCK messages are sent).

If the mobile station has been polled for a PAN, and the data blocks specified for transmission according to the rules in this sub-clause all have corresponding elements in V(B) whose value is TENTATIVE_ACK then no RLC data block shall be transmitted (see sub-clause 8.1.1.).

When an element in V(B) falls outside of the active transmit window, i.e. [ V(A) £ BSN < V(S) ] modulo SNS, the element shall be set to the value INVALID.

When Enhanced Flexible Timeslot Assignment, EFTA, is used, and the applicable conditions for pre-emptive retransmission are true, the mobile station shall not prioritize uplink radio block transmission over attempting to read downlink radio blocks.

9.1.3.2.2 EGPRS TBF running in RLC non-persistent mode

In RLC non-persistent mode, each RLC endpoint transmitter shall have an associated acknowledge state array (V(B)). V(B) is an array of SNS elements indicating the acknowledgement status of WS previous RLC data blocks. The array is indexed relative to the acknowledge state variable V(A) modulo SNS. The values of V(B) shall be updated from the values received from its peer in the reported bitmap (RB) of the Packet Ack/Nack message (see sub-clause 9.1.8). If a compressed reported bitmap is received, decompression shall be first applied according to sub-clause 9.1.10.

The transmitter may transmit any RLC data block included in V(B), e.g. those whose corresponding element in V(B) indexed relative to V(A) has the value NACKED. As each RLC data block is transmitted the corresponding element in V(B) is set to the value PENDING_ACK. If an NPM Transfer Time limitation is associated with the TBF, the transmitting RLC endpoint shall start a timer with a value equal to the NPM Transfer Time (see Table 12.45a.1) each time it begins transmitting a new upper layer PDU. If the timer expires, the transmitting RLC endpoint should not (re)transmit any of the RLC data blocks corresponding to that upper layer PDU and not containing data from other LLC PDU(s) whose timer has not yet expired.

When an element in V(B) falls outside of the active transmit window, i.e. [ V(A) £ BSN < V(S) ] modulo SNS, the element shall be set to the value INVALID.

If the RLC data block to be transmitted is split over two radio blocks, both radio blocks shall be transmitted. The selection of the Puncturing Scheme (PS) shall be performed according to sub-clause 9.3.2.1.

9.1.3.3 Acknowledge State Array V(B) for MBMS Bearers

The RLC endpoint transmitter shall have an associated acknowledge state array (V(B)). V(B) is an array of SNS elements indicating the acknowledgement status of WS previous RLC data blocks. The array is indexed relative to the acknowledge state variable V(A) modulo SNS.

The values of V(B) shall be updated from the values received from its peers in the reported bitmap (RB) of the MBMS DOWNLINK ACK/NACK message (see sub-clause 9.1.8). If a compressed reported bitmap is received, decompression shall be first applied according to sub-clause 9.1.10.

The transmitter may retransmit any RLC data block included in V (B), e.g. those whose corresponding element in V (B) indexed relative to V (A) have the value NACKED. As each RLC data block is transmitted the corresponding element in V (B) is set to the value PENDING_ACK. If an NPM Transfer Time limitation is associated with the MBMS bearer, the transmitting RLC endpoint shall start a timer with a value equal to the NPM Transfer Time (see Table 12. 45a.1) each time it begins transmitting a new upper layer PDU. If the timer expires, the transmitting RLC endpoint should not (re)transmit any of the RLC data blocks corresponding to that upper layer PDU and not containing data from other LLC PDU(s) whose timer has not yet expired.

When an element in V(B) falls outside of the active transmit window, i.e. [ V(A) £ BSN < V(S) ] modulo SNS, the element shall be set to the value INVALID.

For an MBMS bearer running in EGPRS TBF mode, if the RLC data block intended for retransmission is split over two radio blocks, both radio blocks shall be transmitted. The selection of the Puncturing Scheme (PS) shall be performed according to sub-clause 9.3.2.1.

9.1.3.4 Acknowledge State Array V(B) for EC TBF Mode

Each RLC endpoint transmitter shall have an associated acknowledge state array (V(B)). V(B) is an array of SNS elements indicating the acknowledgement status of WS previous RLC data blocks. The array is indexed relative to the acknowledge state variable V(A) modulo SNS. The values of V(B) shall be updated from the values received from its peer in the received block bitmap (RBB) of the Packet Ack/Nack message (see sub-clause 9.1.8.3).

If the transmitter is on the network side the process of pre-emptive retransmission, i.e. retransmitting the oldest RLC data blocks whose value in V(B) has the value PENDING_ACK, is optional.

When an element in V(B) falls outside of the active transmit window, i.e. [ V(A) £ BSN < V(S) ] modulo SNS, the element shall be set to the value INVALID.

9.1.4 Block sequence number BSN

9.1.4.1 Block sequence number BSN for GPRS TBF

Each RLC data block contains a block sequence number (BSN) field that is 7 bits in length. At the time that an in‑sequence RLC data block is designated for transmission, the value of BSN is set equal to the value of the send state variable V(S).

9.1.4.2 Block sequence number BSN for EGPRS TBF

Each RLC data block contains a block sequence number (BSN) field that is 11 bits in length or, for the case of a DLMC configuration where a SNS of 8192 is used (see sub-clause 5.13), 13 bits long.. At the time that an in‑sequence RLC data block is designated for transmission, the value of BSN is set equal to the value of the send state variable V(S).

9.1.4.3 Block sequence number BSN for EC TBF

Each RLC data block contains a block sequence number (BSN) field that is 5 bits in length. At the time that an in‑sequence RLC data block is designated for transmission, the value of BSN is set equal to the value of the send state variable V(S).

9.1.4a Reduced Block Sequence Number RBSN

Each downlink RLC/MAC control block contains a Reduced Block Sequence Number (RBSN) bit. At the time that an in-sequence RLC/MAC control block is designated for transmission, the value of RBSN is set equal to the value of the control send state variable V(CS), except when extended RLC/MAC control message segmentation is used, in which case the value of RBSN is set equal to ‘0’ for the first RLC/MAC control block, and to ‘1’ for the second RLC/MAC control block onwards.

9.1.4b Reduced Block Sequence Number extension RBSNe

When extended RLC/MAC control message segmentation is used, the second to the ninth RLC/MAC control blocks shall contain a Reduced Block Sequence Number extension (RBSNe) field. The first RLC/MAC control block shall not contain a RBSNe field (see sub-clause 10.4.12b). At the time that an in-sequence RLC/MAC control block is designated for transmission, the value of RBSNe is set equal to the value of the control send state variable V(CS) minus 1.

9.1.5 Receive state variable V(R)

Each RLC endpoint receiver shall have an associated receive state variable V(R). The receive state variable denotes the BSN which has a value one higher than the highest BSN of those corresponding to the RLC data blocks so far received (modulo SNS). V(R) shall be set to the value ‘0’ at the beginning of each TBF in which the RLC endpoint is the receiver. V(R) can take on the value 0 through SNS – 1. When EMSR is enabled, a single receive state variable V(R) is maintained regardless of how many PFCs share a given RLC entity.

In RLC acknowledged mode, V(R) shall be set to [ BSN’ + 1 ] modulo SNS, where BSN’ is the highest BSN of those corresponding to received RLC data blocks, provided [ V(R) £ BSN’ < V(Q) + WS ] modulo SNS.

In RLC unacknowledged mode, V(R) shall be set to [ BSN’ + 1 ] modulo SNS, where BSN’ is the highest BSN of those corresponding to received RLC data blocks.

In RLC non-persistent mode, V(R) of each receiving RLC endpoint shall be set to [ BSN’ + 1 ] modulo SNS, where BSN’ is the highest BSN of those corresponding to received RLC data blocks, provided [ V(R) £ BSN’ < V(R) + SNS – WS ] modulo SNS.

9.1.6 Receive window state variable V(Q)

9.1.6.1 General

Each RLC endpoint receiver shall have an associated receive window state variable V(Q). The receive window state variable denotes the lowest BSN not yet received (modulo SNS), therefore representing the start of the receive window. V(Q) shall be set to the value 0 at the beginning of each TBF in which the RLC endpoint is the receiver. The receive window state variable can take on the value 0 through SNS -1.

9.1.6.2 RLC acknowledged mode

In RLC acknowledged mode, the value of V(Q) shall be updated when the RLC receiver receives the RLC data block whose BSN is equal to V(Q). The value of V(Q) shall then be set to the BSN value of the next RLC data block in the receive window (modulo SNS) that has not yet been received, or it shall be set to V(R) if all RLC data blocks in the receive window have been received.

9.1.6.3 RLC unacknowledged mode

In RLC unacknowledged mode, if [V(R) – V(Q)] modulo SNS > WS after updating V(R), then V(Q) is set to [V(R) ‑ WS] modulo SNS.

9.1.6.4 RLC non-persistent mode

In RLC non-persistent mode, V(Q) of each receiving RLC endpoint shall be set to V(R) if all RLC data blocks in the receive window have been received or to BSN’, where BSN’ is the lowest BSN of those corresponding to RLC data blocks not yet received which:

– meets the condition [V(R) – BSN’] modulo SNS  WS and

– it is still expected by the receiving RLC endpoint.

If an NPM Transfer Time limitation is associated with the corresponding MBMS bearer/EGPRS TBF, the receiving RLC endpoint shall start a timer with a value equal to the NPM Transfer Time (see Table 12. 45a.1) for an RLC data block with BSN equal to BSN’ if at the end of a radio block period that data block is first detected as missing i.e. when both of the following conditions are first met for BSN’:

– the RLC data block with sequence number BSN’ has not been received, and

– an RLC/MAC header containing a BSN equal to or higher than BSN’ (modulo SNS) has been received.

The timer shall be started at most once for any given RLC data block. The timer shall not be restarted in the event of an out-of-sequence retransmission (i.e. where the endpoint is expecting a retransmission of that block but receives a retransmission of a block with higher BSN). The timer shall be stopped on reception of the RLC data block.

RLC data blocks are considered not expected if they have been received or (if an NPM Transfer Time limitation is associated with the corresponding MBMS bearer/EGPRS TBF) the corresponding timer has been stopped or has expired.

9.1.7 Receive state array V(N)

9.1.7.1 Receive state array V(N) in GPRS TBF

Each RLC endpoint receiver shall have an associated receive state array V(N). V(N) is an array of SNS elements indicating the receive status of WS previous RLC data blocks. The array is indexed relative to the receive state variable V(R) modulo SNS. When an RLC data block is received with BSN within the receive window, V(R) is treated according to sub-clause 9.1.5 and the element in V(N) corresponding to the received RLC data block is set to the value RECEIVED.

An element in V(N), corresponding to a BSN such that [ V(R)  BSN < V(R) ‑ WS ] modulo SNS, shall be set to the value INVALID.

9.1.7.2 Receive state array V(N) in EGPRS TBF

Each RLC endpoint receiver shall have an associated receive state array V(N). V(N) is an array of SNS elements indicating the receive status of WS RLC data blocks that are supposed to follow the block BSN=V(Q)-1. The array is indexed relative to the receive window state variable V(Q) modulo SNS. When an RLC data block is received with BSN within the receive window, the corresponding element in V(N) is set to the value RECEIVED.

If the RLC data block is split over two radio blocks, the element shall be set to the value RECEIVED if and only if both radio blocks have been received.

The elements in V(N) shall be set to the value INVALID at the beginning of each TBF. During the TBF, an element in V(N) that falls outside the receive window, shall be set to the value INVALID.

9.1.7.3 Receive state array V(N) in TBF with FANR activated

Each RLC endpoint receiver shall have an associated receive state array V(N). V(N) is an array of SNS elements indicating the receive status of RLC data blocks that are supposed to follow the block BSN=V(Q)-1. The array is indexed relative to the receive window state variable V(Q) modulo SNS. When an RLC data block is received with BSN within the receive window, the corresponding element in V(N) shall be set to the value RECEIVED.

If the RLC data block is split over two radio blocks, the element shall be set to the value RECEIVED if and only if both radio blocks have been received.

The elements in V(N) shall be set to the value INVALID at the beginning of each TBF. During the TBF, an element in V(N) that falls outside the receive window shall be set to the value INVALID.

When an EGPRS RLC/MAC header is received, for each BSN’ within the receive window included in the header the elements of V(N) shall be updated as follows:

– if EFTA is not used, or if EFTA is used and the receiving RLC endpoint is in the network, and if the corresponding element in V(N) has the value INVALID, all elements of V(N) with the value INVALID and corresponding to RLC data blocks with BSN satisfying the following inequality [V(Q) ≤ BSN < BSN’] modulo SNS shall be set to the value UNREPORTED;

– if the corresponding element in V(N) has the value REPORTED, all elements of V(N) with the value REPORTED and corresponding to RLC data blocks with BSN satisfying the following inequality [BSN” ≤ BSN < BSN’] modulo SNS shall be set to the value UNREPORTED, where BSN” is:

– the BSN of the newest RLC data block for which the corresponding element in V(N) has the value UNREPORTED, if such a block exists, otherwise

– V(Q).

An element in V(N) whose value is UNREPORTED shall be set to the value REPORTED when the status of the corresponding block is indicated in the RB of a Packet Ack/Nack. This includes the block with BSN = SSN – 1, if the status of that block is implicitly reported in a Packet Ack/Nack.

If the data field of the RLC/MAC block with sequence number BSN’ could not be decoded and the corresponding element in V(N) has the value INVALID or REPORTED, then this element shall also be set to the value UNREPORTED.

NOTE: The elements in V(N) with the value UNREPORTED correspond to RLC data blocks detected as missing due to e.g. the out-of-sequence reception of a data block. The elements in V(N) with the value REPORTED correspond to missing RLC data blocks whose state was indicated in the RB of a Packet Ack/Nack and have not been detected missing since then.

9.1.7.4 Receive state array V(N) in EC TBF

If the RLC data block is split over two radio blocks, the element shall be set to the value RECEIVED if and only if both radio blocks have been received.

The elements in V(N) shall be set to the value INVALID at the beginning of each TBF. During the TBF, an element in V(N) that falls outside the receive window, shall be set to the value INVALID.

9.1.8 Starting sequence number (SSN) and received block bitmap (RBB)

9.1.8.1 Starting sequence number (SSN) and received block bitmap (RBB) in GPRS TBF

The Packet Ack/Nack message contains a starting sequence number (SSN) and a received block bitmap (RBB). The Packet Ack/Nack message is sent by the RLC receiver and is received by the RLC transmitter. The SSN and RBB are determined as defined in this sub-clause and transmitted in RLC acknowledged, RLC unacknowledged and RLC non-persistent modes. The SSN and RBB may be ignored by the RLC transmitter in unacknowledged mode.

The RBB is defined as a binary valued array of WS elements, where the index of each element takes value 0, 1, 2, …, WS-1 in the given order, respectively. The BSN values specified in the RBB are interpreted by subtracting the bit position in the bitmap from the starting sequence number (SSN) modulo SNS.

A valid BSN value in the RBB is one that is in the range [ V(A) £ BSN < V(S) ] modulo SNS.

These inequalities shall be interpreted in the following way:

BSN is valid if, and only if, [ BSN – V(A) ] modulo SNS < [ V(S) – V(A) ] modulo SNS.

At the RLC transmitter:

– For each bit in the RBB whose corresponding BSN value is within the transmit window, if the bit contains the value ‘1’, the corresponding element in V(B) indexed relative to SSN shall be set to the value ACKED. If the bit contains the value ‘0’, the element in V(B) shall be set to the value NACKED. A bit within the RBB whose corresponding BSN is not within the transmit window, shall be ignored. If the RLC transmitter is on the mobile station side, the bit contains the value ‘0’ and the number of block periods between the end of the block period used for the last transmission of the corresponding RLC data block and the beginning of the block period containing the Packet Uplink Ack/Nack message is less than (max(BS_CV_MAX,1) – 1) (i.e. the RLC data block was recently (re)transmitted and thus can not be validly negatively acknowledged in this particular Packet Uplink Ack/Nack message), the element in V(B) shall not be modified.

At the RLC receiver:

– The starting sequence number (SSN) is assigned the value of the receive state variable V(R). The received block bitmap (RBB) is assigned the WS elements whose indices, with incrementing order, correspond to elements in the receive state array V(N) at the receiver whose indices, with decrementing order, range backwards from [ V(R) ‑ 1 ] to [ V(R) ‑ WS ] (modulo SNS). For each bit in the bitmap, the bit is assigned the value ‘1’ if the corresponding element in V(N) indexed relative to SSN has the value RECEIVED. The bit is assigned the value ‘0’ if the element in V(N) has the value INVALID.

– When polled within a downlink RLC data block, the mobile station shall acknowledge all the RLC data blocks for this RLC instance that have been correctly received up to and including the radio block where the mobile station is polled.

– As an implementation option, the mobile station may also acknowledge as many as possible of the RLC data blocks that are correctly received after the radio block where the mobile station is polled.

9.1.8.2 Starting sequence number (SSN) and received block bitmap (RBB) in EGPRS TBF

The Packet Ack/Nack message and MBMS DOWNLINK ACK/NACK message contain a starting sequence number (SSN) and a reported bitmap (RB). When the SSN-based encoding is used (see sub-clause 9.1.14.1), the PAN field included in an EGPRS RLC/MAC block for data transfer contains a short SSN (ShortSSN) and a reported bitmap (RB). The Packet Ack/Nack message, MBMS DOWNLINK ACK/NACK message and PAN field are sent by the RLC receiver and are received by the RLC transmitter. The SSN and RB are determined as defined in this sub-clause and transmitted in RLC acknowledged, RLC unacknowledged and RLC non-persistent modes (note the SSN is calculated differently in EGPRS (refer to table 9.1.8.2.2.1) and GPRS (refer to sub-clause 9.1.8.1)). The SSN and RB may be ignored by the RLC transmitter in unacknowledged mode. For a TBF with FANR activated, the ShortSSN (and corresponding SSN) is determined as defined in sub-clause 9.1.8.2.2a and the RB is determined as defined for EGPRS (see sub-clause 9.1.8.2.3). The ShortSSN and RB fields are transmitted in both RLC acknowledged and RLC non-persistent modes.

The BSN values specified in the RB are interpreted by adding the bit position in the bitmap to the starting sequence number (SSN) modulo SNS (where the first position of the bitmap has index ‘0’). A valid BSN value in the RB is one that is in the range [ V(A) £ BSN < V(S) ] modulo SNS. These inequalities shall be interpreted in the following way: BSN is valid if, and only if, [BSN – V(A) ] modulo SNS < [ V(S) – V(A) ] modulo SNS.

9.1.8.2.1 Extended Polling

For EGPRS uplink TBFs, the network may select any composition of the Packet Ack/Nack message to send to the mobile station. In EGPRS downlink TBFs and MBMS bearers running in EGPRS TBF mode, the ES/P field present in every downlink RLC block allows the network to request one of the following Ack/Nack bitmap types:

– First Partial Bitmap (FPB) segment with SSN = (V(Q) + 1) mod SNS (the beginning of the window is V(Q) but FPB starts at V(Q) + 1 as the bit in the bitmap corresponding to V(Q) would have value ‘0’) where SSN denotes the Starting Sequence Number.

– Next Partial Bitmap (NPB) segment with SSN = (PBSN + 1) mod SNS where PBSN denotes a Partial Bitmap Sequence Number variable stored at the receiver.

SSN is determined by the receiver as a function of ES/P, V(Q) and PBSN as described in the next sub-clause. The FPB and NPB are specific instances of the EGPRS Ack/Nack Description Information Element within the EGPRS PACKET DOWNLINK ACK/NACK message, EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message, EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message or MBMS DOWNLINK ACK/NACK message or specific instances of the EGPRS Ack/Nack Description DLMC Information Element within the EGPRS PACKET DOWNLINK ACK/NACK DLMC message. The mobile station shall respond to ES/P field according to table 9.1.8.2.1.1 (non-MBMS) or table 9.1.8.2.1.2 (MBMS). For a mobile station with one or more downlink TBFs using EGPRS2, the mobile station shall send the EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message or the EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message. A mobile station in a DLMC configuration using an SNS of 2048 shall always send the EGPRS PACKET DOWNLINK ACK/NACK DLMC message. Otherwise, the mobile station shall send the EGPRS PACKET DOWNLINK ACK/NACK message or the EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message.

Table 9.1.8.2.1.1: Format of ES/P field within each EGPRS RLC block (non-MBMS)

ES/P	Feedback Request (Poll) Description
00	Nothing (RRBP field invalid)
01	EGPRS PACKET DOWNLINK ACK/NACK message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message or EGPRS PACKET DOWNLINK ACK/NACK DLMC message containing FPB (First Partial Bitmap), and if there is enough room left in RLC/MAC block, channel quality report(s)
10	EGPRS PACKET DOWNLINK ACK/NACK message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message or EGPRS PACKET DOWNLINK ACK/NACK DLMC message containing NPB (Next Partial Bitmap), and if there is enough room left in RLC/MAC block, channel quality report(s)
11	EGPRS PACKET DOWNLINK ACK/NACK message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message or EGPRS PACKET DOWNLINK ACK/NACK DLMC message containing Channel Quality Report and if there is enough room left in RLC/MAC block, NPB(s)

In a downlink dual carrier configuration the MS shall send channel quality reports for both carriers, if there is room in the message. If there is room for only one channel quality report, the MS shall include channel quality measurements for the radio frequency channel on which the poll was received.

Table 9.1.8.2.1.2: Format of ES/P field within each EGPRS RLC block (MBMS)

ES/P	Feedback Request (Poll) Description
00	Nothing (RRBP field invalid)
01	MBMS DOWNLINK ACK/NACK message containing FPB (First Partial Bitmap)
10	MBMS DOWNLINK ACK/NACK message containing NPB (Next Partial Bitmap)
11	MBMS DOWNLINK ACK/NACK message containing neighbour cell measurement reports and NPB

For EGPRS when FANR is activated or for EGPRS2, the Combined EGPRS Supplementary/Polling field describes the feedback request and specifies a single uplink block in which the mobile station shall transmit a PACKET CONTROL ACKNOWLEDGEMENT message, a PACCH block or (applicable only if FANR is activated) a radio block containing a PAN field to the network, see table 9.1.8.2.1.3. The single uplink block is defined by a delay relative to the first TDMA frame (N) of the downlink block containing the CES/P value. If ordered to send an EGPRS PACKET DOWNLINK ACK/NACK message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message, a mobile station with one or more downlink TBFs using EGPRS2 shall send the EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message. A mobile station in a DLMC configuration using an SNS of 2048 shall always send the EGPRS PACKET DOWNLINK ACK/NACK DLMC message. Otherwise, the mobile station shall send the EGPRS PACKET DOWNLINK ACK/NACK message.

Table 9.1.8.2.1.3: Format of CES/P field within each EGPRS RLC block (EGPRS with FANR activated and EGPRS2)

CES/P	Feedback Request (Poll) Description and Relative Reserved Block Period
000	Nothing
001	EGPRS PACKET DOWNLINK ACK/NACK message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message or EGPRS PACKET DOWNLINK ACK/NACK DLMC message containing FPB, and if there is enough room left in RLC/MAC block, channel quality report(s) within the radio period (N+8 or N+9) mod 2715648 in the BTTI configuration or (N+6 or N+7) mod 2715648 in the RTTI configuration
010	EGPRS PACKET DOWNLINK ACK/NACK message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message or EGPRS PACKET DOWNLINK ACK/NACK DLMC message containing FPB, and if there is enough room left in RLC/MAC block, channel quality report(s) within the radio period (N+13) mod 2715648 in the BTTI configuration or (N+8 or N+9) mod 2715648 in the RTTI configuration
011	EGPRS RLC/MAC block for data transfer with a PAN field containing FPB within the radio period (N+8 or N+9) mod 2715648 in the BTTI configuration or (N+6 or N+7) mod 2715648 in the RTTI configuration (NOTE 1)
100	EGPRS RLC/MAC block for data transfer with a PAN field containing FPB within the radio period (N+13) mod 2715648 in the BTTI configuration or (N+8 or N+9) mod 2715648 in the RTTI configuration (NOTE 1)
101	EGPRS PACKET DOWNLINK ACK/NACK message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message or EGPRS PACKET DOWNLINK ACK/NACK DLMC message containing Channel Quality Report(s) and if there is enough room left in RLC/MAC block, NPB within the radio period (N+8 or N+9) mod 2715648 in the BTTI configuration or (N+6 or N+7) mod 2715648 in the RTTI configuration (NOTE 2)
110	EGPRS PACKET DOWNLINK ACK/NACK message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message or EGPRS PACKET DOWNLINK ACK/NACK DLMC message containing Channel Quality Report(s) and if there is enough room left in RLC/MAC block, NPB within the radio period (N+13) mod 2715648 in the BTTI configuration or (N+8 or N+9) mod 2715648 in the RTTI configuration (NOTE 2)
111	EGPRS PACKET DOWNLINK ACK/NACK message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message or EGPRS PACKET DOWNLINK ACK/NACK DLMC message containing NPB, and if there is enough room left in RLC/MAC block, channel quality report(s) within the radio period (N+8 or N+9) mod 2715648 in the BTTI configuration or (N+6 or N+7) mod 2715648 in the RTTI configuration (NOTE 2)
NOTE 1: The mobile station shall ignore the poll for PAN in the case when received for a TBF with FANR not activated. NOTE 2: The mobile station shall not truncate the EGPRS Ack/Nack Description IE in the EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message (see sub-clause 11.2.6e) or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message (see sub-clause 11.2.6f) that would contain a final Ack indicator set to ‘1’.

A mobile station in DLMC configuration using an SNS of 8192 shall respond to the feedback request indicated by the CES/P field within the RLC data block header (see sub-clause 10.3a.3.1, 10.3a.3.2, 10.3a.3.3, 10.3a.3.4, 10.3a.3.5 and 10.3a.3.10) as shown in Table 9.1.8.2.1.4.

Table 9.1.8.2.1.4: Format of CES/P field within each DLMC EGPRS RLC block (EGPRS with FANR activated and EGPRS2

CES/P	Feedback Request (Poll) Description and Relative Reserved Block Period
00	Nothing
01	EGPRS PACKET DOWNLINK ACK/NACK DLMC message containing FPB, and if there is enough room left in the RLC/MAC block, channel quality report(s) within the radio period (N+8 or N+9) mod 2715648 in the BTTI configuration or (N+6 or N+7) mod 2715648 in the RTTI configuration
10	EGPRS PACKET DOWNLINK ACK/NACK DLMC message containing Channel Quality Report(s) and if there is enough room left in the RLC/MAC block, NPB within the radio period (N+8 or N+9) mod 2715648 in the BTTI configuration or (N+6 or N+7) mod 2715648 in the RTTI configuration (NOTE 1)
11	EGPRS RLC/MAC block for data transfer with a PAN field containing FPB within the radio period (N+8 or N+9) mod 2715648 in the BTTI configuration or (N+6 or N+7) mod 2715648 in the RTTI configuration (NOTE 2)
NOTE 1: The mobile station shall not truncate the EGPRS Ack/Nack Description IE in the EGPRS PACKET DOWNLINK ACK/NACK DLMC message (see sub-clause 11.2.48) that would contain a final Ack indicator set to ‘1’. NOTE 2: The mobile station shall ignore the poll for PAN in the case when received for a TBF with FANR not activated.

In a DLMC configuration, when the MS sends channel quality report information it shall use the value of the DLMC Measurement Type field (see sub-clause 11.2.7) within the most recently received assignment message as follows:

– If this field indicates measurement information is to be reported on a per UFPS basis the MS shall always include channel quality measurements for the UFPS corresponding to the radio frequency channel on which the poll was received. If there is room in the message (see sub-clause 11.2.48) the MS shall report additional higher numbered UFPS (if any) beginning with the next in sequence UFPS (see sub-clause 8.1.1.1.3 for the numbering of UFPS and 3GPP TS 45.008 [15] for how DLMC BEP Link Quality Measurements are reported on a per UFPS basis).

– If this field indicates measurement information is to be reported on a per carrier basis the MS shall always include channel quality measurements for the carrier corresponding to the radio frequency channel on which the poll was received. If there is room in the message (see sub-clause 11.2.48) the MS shall report additional higher numbered carriers (if any) beginning with the next in sequence carrier (see sub-clause 8.1.1.1.3 for the numbering of downlink carriers in a DLMC configuration).

For MBMS bearers, in case cell re-selection criteria are not fulfilled (see 3GPP TS 45.008):

– If the ES/P field is set to ‘11’ the mobile station shall include measurement reports for at least three neighbouring cells in addition to the NPB. If the complete NPB is included, the mobile station shall include measurement results for more neighbouring cells, if there is sufficient space;

– Else (i.e. the ES/P field is set to ‘01’ or ‘10’) the mobile station shall send as much of either the FPB or NPB (as specified in Table 9.1.8.2.1.2) as possible and, if the entire FPB/NPB is sent, measurement reports for as many neighbouring cells as can also be included.

For MBMS bearers, in case cell re-selection criteria are fulfilled towards a neighbouring cell (see 3GPP TS 45.008), the mobile station if polled shall include in the MBMS DOWNLINK ACK/NACK message the measurement report only for that cell and as much of either the First Partial Bitmap (FPB) or Next Partial Bitmap (NPB) (as specified in Table 9.1.8.2.1.2) as possible.

9.1.8.2.2 Determination of SSN

If the receiving side is the network, the network may select any SSN within the receive window. If the receiving side is the mobile station, SSN shall be determined as follows: Let PBSN represent a Partial Bitmap Sequence Number variable stored at the receiver which helps to determine the Starting Sequence Number (SSN) for the next partial bitmap to be transmitted. Based on PBSN, V(Q) and the ES/P field set by the network, SSN and PBSN shall be determined according to table 9.1.8.2.2.1. For EGPRS when FANR is activated and for EGPRS2, SSN and PBSN shall be determined based on PBSN, V(Q) and CES/P fields according to table 9.1.8.2.2.2 and 9.1.8.2.2.3.

Table 9.1.8.2.2.1: Determination of SSN as a function of ES/P, V(Q) and PBSN

Full bitmap (compressed or not)	ES/P	Determination of SSN
–	00	–
fits in available space	01, 10, 11	Set SSN = (V(Q)+1) modulo SNS set PBSN = V(Q).
does not fit in available space	01	Set SSN = (V(Q)+1) modulo SNS, set PBSN = last sequence number for which Ack/Nack status can be indicated in available space in EGPRS PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC or MBMS DOWNLINK ACK/NACK message.
	10, 11	If (PBSN+1)modulo SNS =V(Q) or (PBSN+1) modulo SNS lies outside the receiver windowset SSN = (V(Q)+1) modulo SNS, else set SSN = (PBSN+1) modulo SNS and set PBSN = last sequence number for which Ack/Nack status can be indicated in available space in EGPRS PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC or MBMS DOWNLINK ACK/NACK message.

Table 9.1.8.2.2.2: Determination of SSN as a function of CES/P, V(Q) and PBSN

Full bitmap (compressed or not)	CES/P	Determination of SSN
–	000	–
fits in available space	001, 010, 101, 110, 111	Set SSN = (V(Q)+1) modulo SNS set PBSN = V(Q).
does not fit in available space	001, 010	Set SSN = (V(Q)+1) modulo SNS, set PBSN = last sequence number for which Ack/Nack status can be indicated in available space in EGPRS PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or MBMS DOWNLINK ACK/NACK message.
	101, 110, 111	If (PBSN+1)modulo SNS =V(Q) or (PBSN+1) modulo SNS lies outside the receiver windowset SSN = (V(Q)+1) modulo SNS, else set SSN = (PBSN+1) modulo SNS and set PBSN = last sequence number for which Ack/Nack status can be indicated in available space in EGPRS PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or MBMS DOWNLINK ACK/NACK message. (see Note)
NOTE: For a TBF with FANR activated, the CES/P combinations ‘011’ and ‘100’ mean the mobile station is polled for a PAN (see sub-clause 10.4.4b). If the mobile station responds to the poll by transmitting an EGPRS RLC/MAC block for data transfer with a PAN field included (see sub-clause 8.1.2.2), SSN is determined as specified in sub-clause 9.1.8.2.2a. For a TBF with FANR not activated, the CES/P combinations ‘011’ and ‘100’ shall be ignored by the mobile station.

Table 9.1.8.2.2.3: Determination of SSN as a function of CES/P, V(Q) and PBSN (DLMC configuration using an SNS of 8192)

Full bitmap (compressed or not)	CES/P	Determination of SSN
–	00	–
fits in available space	01, 10	Set SSN = (V(Q)+1) modulo SNS set PBSN = V(Q).
does not fit in available space	01	Set SSN = (V(Q)+1) modulo SNS, set PBSN = last sequence number for which Ack/Nack status can be indicated in available space in EGPRS PACKET DOWNLINK ACK/NACK DLMC message.
	10	If (PBSN+1)modulo SNS =V(Q) or (PBSN+1) modulo SNS lies outside the receiver window set SSN = (V(Q)+1) modulo SNS, else set SSN = (PBSN+1) modulo SNS and set PBSN = last sequence number for which Ack/Nack status can be indicated in available space in EGPRS PACKET DOWNLINK ACK/NACK DLMC. (see NOTE 1)
NOTE 1: The CES/P value ‘11’ indicates the mobile station is polled for a PAN (see sub-clause 10.4.4b). If the mobile station responds to the poll by transmitting an EGPRS or EGPRS2 RLC/MAC block for data transfer with a PAN field included (see sub-clause 8.1.2.2), SSN is determined as specified in sub-clause 9.1.8.2.2a.

When a next partial bitmap needs to be transmitted in response to a poll, it may turn out that (V(R)-PBSN) mod SNS is much smaller than the available space. In such cases, a larger amount of feedback can be provided as an implementation option if the receiver backtracks from PBSN and represents as much of the V(Q) to PBSN range as possible, in addition to the PBSN to V(R) range, possibly using compression. If backtracking is carried out, the SSN must be properly indicated within the Ack/Nack description in order to allow the transmitter to accurately interpret the feedback. For MBMS Bearers, this option may only apply if the cell re-selection criteria are fulfilled (see 3GPP TS 45.008).

9.1.8.2.2a Determination of ShortSSN and SSN in the Piggy-backed Ack/Nack field

If the receiving side is the network, the network may select any SSN within the receive window. If the receiving side is the mobile station, SSN shall be determined as follows.

In case of polled FANR (see sub-clause 9.1.14.2), SSN shall be set to V(Q) + 1.

In case of event-based FANR, the SSN shall be set to the following value (where BSN’ is the BSN of the oldest RLC data block of which the corresponding element in V(N) has the value UNREPORTED, and N is the number of bits in the bitmap):

– the higher of V(Q) + 1 and V(R) – N, provided that the bitmap includes BSN’, else

– BSN’ + 1, if V(Q) is equal to BSN’, else

– BSN’, if V(Q) is not equal to BSN’.

The ShortSSN shall then be set to the value of the L least significant bits of SSN. The number L of bits is determined as defined in sub-clause 10.4.23.

9.1.8.2.3 Generation of the bitmap

First, a Full Received Bitmap (FRB) is built from the receive state array V(N) by extracting the part between V(Q) and V(R) similar to the GPRS case: it is assigned the elements whose indices in the receive state array V(N) at the receiver range from [V(Q)+ 1] to [V(R) -1] (modulo SNS). For each bit in the bitmap, the bit is assigned the value ‘1’ if the corresponding element in V(N) indexed relative to SSN has the value RECEIVED. The bit is assigned the value ‘0’ if the element in V(N) has the value INVALID. For a TBF with FANR activated, the bit is assigned the value ‘0’ also if the element in V(N) has the value UNREPORTED or REPORTED.

For EGPRS TBFs for which FANR is not active and for which neither downlink dual carrier configuration nor DLMC configuration nor EGPRS2 nor TBFs running in RLC non-persistent mode are used, the same principles and implementation options as for GPRS apply regarding the determination of V(R).

For EGPRS TBFs for which FANR is not active and for which either downlink dual carrier configuration, or DLMC configuration or EGPRS2 or RLC non-persistent mode are used, when the mobile station is polled, V(R) shall be determined taking into account all RLC data blocks received up to and including those received in the radio block period where the poll is received.

For EGPRS TBFs for which FANR is active, V(R) and therefore the bitmap shall be determined taking into account all RLC data blocks received up to and including those received in the reduced radio block period m-2 for RTTI configuration, and those received in the basic radio block period m-2 for BTTI configuration, where the bitmap is sent in radio block period m.

From the FRB, a reported bitmap (RB) shall then be generated. The FRB shall be recalculated before each RB is generated, except that PAN fields transmitted during the same radio block period for the same TBF shall be based on the same FRB and the FRB shall therefore not be recalculated between the generation of these PAN fields. Different lengths of RBs exist (see clause 12 and sub-clause 10.3a.5). For uplink TBFs, the network may transmit any RB size to the mobile station. For downlink TBFs, the network may order the mobile station to transmit a certain RB size through use of the ES/P field. The bitmap size may be selected based on e.g. risk of protocol stalling. The RB in a PAN field is always uncompressed. In EGPRS PACKET DOWNLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK TYPE 2, EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 messages, and EGPRS PACKET DOWNLINK ACK/NACK DLMC the RB is one of the following types:

a) Uncompressed reported bitmap:

If the range of indices from SSN to the end of FRB is less than or equal to N bits, where N is the reported bitmap size, the RB starts at SSN and covers the range of indices from SSN to the end of FRB. When an RB is a part of a PAN field, if the number of indices from SSN to the end of FRB is less than N bits and the reported bitmap is generated by the mobile station, the bits not covering the FRB shall be set to the value ‘0’. When an RB is a part of a PAN field, if the number of indices from SSN to the end of FRB is less than N bits and the reported bitmap is generated by the network, the bits not covering the FRB shall be set to the value ‘1’, If the range of indices from SSN to the end of FRB is greater than N bits, the RB is assigned the first N bits of the FRB starting at SSN.

b) Compressed reported bitmap:

Using the compression algorithm, the receiver generates RB of length N bits starting at SSN, where N is the reported bitmap size used.

If the compressed reported bitmap covers more blocks than the uncompressed reported bitmap, the receiver shall send the compressed reported bitmap, otherwise the receiver shall send the uncompressed reported bitmap. As an exception, if the FRB length or the range of indices from SSN to the end of FRB is less than or equal to N bits, the receiver may send the uncompressed reported bitmap without attempting compression.

The BOW (begin of window) bit shall be set if SSN = [V(Q) + 1] modulo SNS, the EOW (end of window) bit shall be set if [V(R) -1] modulo SNS is explicitly included in the bitmap.

If V(Q) equals V(R), then SSN shall be set to the value SSN = [V(Q) + 1] modulo SNS, BOW bit shall be set to the value ‘1’, EOW shall be set to the value ‘1’ and the reported bitmap size shall equal 0 bits.

For uplink TBFs, the reported bitmap is sent using the PACKET UPLINK ACK/NACK message corresponding to the used RB size.

For downlink TBFs the reported bitmap is sent using the EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message for mobiles with one or more downlink TBFs using EGPRS2, or using EGPRS PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 message otherwise. For MBMS bearers the reported bitmap is sent using the MBMS DOWNLINK ACK/NACK message. For a DLMC configuration the reported bitmap is sent using the EGPRS PACKET DOWNLINK ACK/NACK DLMC message.

9.1.8.2.4 Interpretation of the bitmap

If a compressed reported bitmap is received, the bitmap shall first be decompressed according to sub-clause 9.1.10. The uncompressed bitmap shall then be treated as follows:

Firstly, if the BOW bit in PACKET UPLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC message has the value ‘1’, then the bitmap acknowledges all blocks between V(A) and (SSN- 2) (modulo SNS), and the corresponding elements in V(B) shall be set to the value ACKED. Also a bitmap value of ‘0’ is assumed at the bit position corresponding to (SSN-1) modulo SNS which corresponds to V(Q). If the BOW bit in MBMS DOWNLINK ACK/NACK message has the value ‘1’, then the bitmap acknowledges all blocks between V(A) and (SSN-2) (modulo SNS), and a bitmap value of ‘0’ is assumed at the bit position corresponding to (SSN-1) modulo SNS, only for the mobile station sending the message. The decision whether to set the corresponding elements in V(B) to the value ACKED is implementation specific.

Then, in case of PACKET UPLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC message, for each bit in the uncompressed bitmap whose corresponding BSN value is within the transmit window, if the bit contains the value ‘1’, the corresponding element in V(B) indexed relative to SSN shall be set to the value ACKED. If the bit contains the value ‘0’, the element in V(B) shall be set to the value NACKED. A bit within the uncompressed bitmap whose corresponding BSN is not within the transmit window, shall be ignored. In case of MBMS DOWNLINK ACK/NACK message, for each bit in the uncompressed bitmap whose corresponding BSN value is within the transmit window, if the bit contains the value ‘1’, it positively acknowledges the corresponding RLC data block only for the mobile station sending the message, and the decision whether to set to the value ACKED the corresponding element in V(B) indexed relative to SSN is implementation specific. If the bit contains the value ‘0’, it negatively acknowledges the corresponding RLC data block only for the mobile station sending the message, and the decision whether to set to the value NACKED the corresponding element in V(B) indexed relative to SSN is implementation specific. A bit within the uncompressed bitmap whose corresponding BSN is not within the transmit window shall be ignored.

If the EOW bit in the PACKET UPLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK TYPE 2, EGPRS PACKET DOWNLINK ACK/NACK TYPE 3, EGPRS PACKET DOWNLINK ACK/NACK DLMC or MBMS DOWNLINK ACK/NACK message has the value ‘1’, then bitmap value ‘0’ shall be assumed for all RLC blocks with a BSN value higher than the last entry in the bitmap but less than V(S) (i.e. [ V(R) – 1 < BSN < V(S)] modulo SNS).

If the RLC transmitter is on the mobile station side, the bit in the bitmap contains the value ‘0’ and the number of block periods between the end of the block period used for the last transmission of the corresponding RLC data block and the beginning of the block period containing the PACKET UPLINK ACK/NACK message is less than (max(BS_CV_MAX,1) – 1) (i.e. the RLC data block was recently (re)transmitted and thus can not be validly negatively acknowledged in this particular PACKET UPLINK ACK/NACK message), the element in V(B) shall not be modified. Similarly, if the RLC transmitter is on the network side and the RLC data block cannot be validly negatively acknowledged in this particular Packet Ack/Nack message the element in V(B) shall not be modified.

In the case of a PAN field, the bitmap shall be interpreted in the same way as for the case of PACKET UPLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK TYPE 2, EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC message with the following exceptions:

– in the case when the PAN is received by the network, in RLC acknowledged mode, elements of V(B) shall not be set to ACKED; any element which would be set to ACKED shall be set to TENTATIVE_ACK;

– in the case when the PAN is received by the mobile station, the contents of the reported bitmap shall be validated assuming a BS_CV_MAX value of 2, regardless of the value of the signalled BS_CV_MAX parameter;

– in the case when the PAN is received by the mobile station, the value ‘1’ received in the reported bitmap shall not modify the current value of the corresponding element in V(B); the value ‘0’ received in the reported bitmap shall set the corresponding element in V(B) to the value NACKED; in RLC acknowledged mode and when the BOW is set to the value ‘1’ then all elements in V(B) corresponding to all blocks between V(A) and (SSN- 2) (modulo SNS) shall be set to the value TENTATIVE_ACK;

– if the processing of a PAN would cause an element of V(B) to be changed from ACKED or TENTATIVE_ACK to NACKED, the entire PAN field shall be ignored;

– if a PAN positively acknowledges a block which has not yet been transmitted (i.e. whose BSN is higher than or equal to V(S)) the entire PAN field shall be ignored;

– if a time-based PAN indicates a reserved value the entire PAN field shall be ignored.

NOTE: The last three conditions may arise due to undetected error in the PANI or in the PAN field.

9.1.8.3 Starting sequence number (SSN) and received block bitmap (RBB) in EC TBF

The RBB is defined as a binary valued array of WS elements (see sub-clause 12.72), where the index of each element takes value 0, 1, 2, …, WS-1 in the given order, respectively, or a binary valued array of WS/2 elements (see sub-clause 12.73), where the index of each element takes value 0, 1, 2, …, WS/2-1 in the given order, respectively. The BSN values specified in the RBB are interpreted by adding the bit position in the bitmap from the starting sequence number (SSN) modulo SNS.

A valid BSN value in the RBB is one that is in the range [ V(A) < BSN < V(S) ] modulo SNS.

These inequalities shall be interpreted in the following way:

BSN is valid if, and only if, ([ BSN – V(A) ] modulo SNS < [ V(S) – V(A) ] modulo SNS) and (BSN != V(A)).

At the RLC transmitter:

– For each bit in the RBB whose corresponding BSN value is within the transmit window, if the bit contains the value ‘1’, the corresponding element in V(B) indexed relative to SSN shall be set to the value ACKED. If the bit contains the value ‘0’, the element in V(B) shall be set to the value NACKED. All blocks between V(A) and (SSN- 2) (modulo SNS) shall be considered acknowledged, and the corresponding elements in V(B) shall be set to the value ACKED. Also a bitmap value of ‘0’ is assumed at the bit position corresponding to (SSN-1) modulo SNS, which corresponds to V(Q). A bit within the RBB whose corresponding BSN is not within the transmit window, shall be ignored.

At the RLC receiver:

– The starting sequence number (SSN) is assigned the value (V(Q)+1) modulo SNS. The received block bitmap (RBB) is assigned the elements whose indices in the receive state array V(N) at the receiver range from [V(Q)+ 1] to [V(R) -1] (modulo SNS). For each bit in the bitmap, the bit is assigned the value ‘1’ if the corresponding element in V(N) indexed relative to SSN has the value RECEIVED. The bit is assigned the value ‘0’ if the element in V(N) has the value INVALID.

9.1.9 Window Size

9.1.9.1 GPRS

For GPRS, the window size (WS) shall be 64.

9.1.9.2 EGPRS

A mobile station may support the use of the GPRS multislot class also for the EGPRS-GMSK only TBF mode. The support of this feature must be indicated as the "Modulation based multislot class support" information in the MS Radio Access Capability IE and the MS Radio Access Capability 2 IE.

A mobile station in EGPRS TBF mode not supporting the "Modulation based multislot class support" shall apply the EGPRS multislot class. A mobile station in EGPRS-GMSK only TBF mode shall apply the GPRS multislot class.

While a EGPRS-GMSK only TBF mode is in progress, if a mobile station receives DL blocks not coded with modulation and coding scheme MCS-1 to MCS-4 then the MS behavior is implementation specific.

For EGPRS the window size (WS) shall be set by the network according to the number of timeslots assigned in the direction of the TBF (uplink or downlink) using the applicable multislot capability except for the case of a DLMC configuration where the window size is determined by the buffer size supported (see Table 9.1.9.3.2). The allowed window sizes are given in table 9.1.9.2.1. Preferably, the selected window size should be the maximum, or follow the definition in annex I.

The window size may be set independently for each TBF on uplink and downlink. The mobile station shall support the maximum window size corresponding to its multislot capability. The selected WS shall be indicated within a PACKET UL/DL ASSIGNMENT, MULTIPLE TBF UL/DL ASSIGNMENT, PACKET TIMESLOT RECONFIGURE, MULTIPLE TBF TIMESLOT RECONFIGURE or PACKET CS RELEASE INDICATION message using the coding defined in table 9.1.9.2.1 except for the case of a DLMC configuration where the window size is determined by the buffer size supported (see Table 9.1.9.3.2).

Once a window size is selected for a given TBF, it may be changed to a larger size but not to a smaller size, in order to prevent dropping data blocks from the window.

In case the MS multislot class is not indicated during packet data connection establishment (access request for signalling message transfer), a default window size corresponding to the minimum window size for 1 timeslot (as defined in table 9.1.9.2.1) shall be selected.

In case a PACKET TIMESLOT RECONFIGURE or MULTIPLE TBF TIMESLOT RECONFIGURE message is sent to the mobile station without any window size for a specific TBF, then any previous value received for the specific TBF shall be used or, if no previous value has been received for the specific TBF, default window size shall be used.

NOTE: If a TBF is reallocated so that the number of assigned timeslots is reduced, the RLC window size may become larger than the maximum window size for the new resources.

Table 9.1.9.2.1: Allowed window sizes in EGPRS TBF mode for different multislot allocations

Window size	Coding	Timeslots assigned (multislot capability)
Window size	Coding	1	2	3	4	5	6	7	8
64	00000
96	00001
128	00010
160	00011
192	00100	Max
224	00101
256	00110		Max
288	00111
320	01000
352	01001
384	01010			Max
416	01011
448	01100
480	01101
512	01110				Max
544	01111
576	10000
608	10001
640	10010					Max
672	10011
704	10100
736	10101
768	10110						Max
800	10111
832	11000
864	11001
896	11010							Max
928	11011
960	11100
992	11101
1024	11110								Max
Reserved	11111	x	x	x	x	x	x	x	X
NOTE: The shaded cells represent the allowed window sizes.

9.1.9.2a EC-GSM-IoT

For EC-GSM-IoT, i.e. for an EC TBF, the window size (WS) shall be 16.

9.1.9.3 RLC buffer

A mobile station supporting multiple TBF or EMST shall support one RLC buffer per direction (uplink and downlink). The RLC buffer in a given direction represents the amount of physical memory the mobile station shall support in this direction for RLC PDUs from all RLC instances in the transmit (uplink) or receive (downlink) window(s). The RLC buffer size is given as the maximum number of RLC data blocks that can be stored in this buffer assuming the highest (modulation and) coding scheme supported by the mobile station in this direction. The RLC buffer shall be as follows:

– A mobile station supporting GPRS (not supporting EGPRS) shall support a RLC buffer of size 64 in both uplink and downlink directions

– A mobile station supporting EGPRS shall support RLC buffers as defined in the Table 9.1.9.3.1 below

– A mobile station in DLMC configuration shall support RLC buffers in the uplink as defined in Table 9.1.9.3.1 and RLC buffers in the downlink as defined in Table 9.1.9.3.2.

– A mobile station supporting EC-GSM-IoT (not supporting GPRS or EGPRS) shall support a RLC buffer of size 16 in both uplink and downlink directions.

Table 9.1.9.3.1: RLC buffer in a given direction for EGPRS capable MS

	Maximum amount N of timeslots the MS supports in this direction (see note 1)
	1	2	3	4	5	6	7	8
RLC buffer size S (see note 2)	192	256	384	512	640	768	896	1024
NOTE 1: See 3GPP TS 45.002 for multislot classes NOTE 2: An EGPRS capable mobile station able to support up to N timeslots in a direction shall support an RLC buffer in this direction that can store S RLC data blocks

Table 9.1.9.3.2: Downlink RLC buffer for MS in DLMC Configuration

	Maximum number of downlink timeslots supported (see note 1)
	6 – 20	21 – 26	27 – 32	More than 32
RLC buffer size S (see note 2)	1024	2048	3072	4096
NOTE 1: See MS Radio Access Capability IE in 3GPP TS 24.008 NOTE 2: A mobile station that supports up to N downlink timeslots in DLMC configuration shall support an RLC buffer that can store S RLC data blocks

NOTE: The sum of the RLC window sizes of all RLC instances running in the mobile station in a given direction may be larger than the mobile station’s RLC buffer in this direction. The RLC buffer does not affect the allocation of RLC window size.

9.1.10 Compression

The compression algorithm is as follows. If the window size is less than the number of bits available for the bitmap, then full feedback is provided using an uncompressed bitmap. If the window size is larger than the number of bits available for the bitmap, then one-dimensional run length coding (based on ITU-T Recommendation T.4) is carried out starting at SSN.

The T.4 procedure for encoding run lengths is as follows. Runs of ones and zeros alternate, and the run lengths are represented by the code words listed in the tables below. The code words for run lengths of zeros and ones are as described in T.4 except for one minor modification: the terminating code words used for indicating run lengths of 1 zero and 3 zeros are interchanged. This modification helps in achieving some throughput improvement when frequency hopping is carried out. The run length code words are of two types: terminating code words and make-up code words. Each run length is represented by either one terminating code word or one make-up code word followed by a terminating code word. Run lengths in the range 0-63 bits are encoded with their appropriate terminating code word. Run lengths greater than 63 bits are encoded first by the make-up code word which is equal to or shorter than that required. This is then followed by the terminating code word representing the difference between the required run length and the run length represented by the make-up code.

No special code words are used either at the beginning of the bitmap or the end of a bitmap. A one bit indicator (i.e. Compressed Bitmap Starting Color Code) is used to indicate whether the compressed bitmap starts with a run length of zeros or a run length of ones.

The compressed bitmap is assumed to be of length Lc (see clause 12) bits. The run length encoder output is used only if a compression gain is realized; otherwise an uncompressed partial bitmap is transmitted. The compressed portion of the bitmap must end on a T.4 code word boundary which may or may not coincide with the number of bits available. In such cases, one possible implementation is to recognize the boundary of the last valid T.4 code word that fits into the available space as the end of the compressed bitmap. The rest of the bitmap is assumed to be uncompressed; the uncompressed portion of the bitmap has variable length (see clause 12). Any bits representing sequence numbers V(R) or beyond in either the compressed or uncompressed portion of the bitmap must be set to 0. Implementations may use other schemes to determine the boundary between the compressed and uncompressed portions of the bitmap.

Table 9.1.10.1: Terminating codes (reproduced from ITU-T Recommendation T.4);
T.4 code words used for representing run lengths of 1 zero and 3 zeros are interchanged

One run length	Code word	Zero run length	Code word
0	00110101	0	0000110111
1	000111	1	10
2	0111	2	11
3	1000	3	010
4	1011	4	011
5	1100	5	0011
6	1110	6	0010
7	1111	7	00011
8	10011	8	000101
9	10100	9	000100
10	00111	10	0000100
11	01000	11	0000101
12	001000	12	0000111
13	000011	13	00000100
14	110100	14	00000111
15	110101	15	000011000
16	101010	16	0000010111
17	101011	17	0000011000
18	0100111	18	0000001000
19	0001100	19	00001100111
20	0001000	20	00001101000
21	0010111	21	00001101100
22	0000011	22	00000110111
23	0000100	23	00000101000
24	0101000	24	00000010111
25	0101011	25	00000011000
26	0010011	26	000011001010
27	0100100	27	000011001011
28	0011000	28	000011001100
29	00000010	29	000011001101
30	00000011	30	000001101000
31	00011010	31	000001101001
32	00011011	32	000001101010
33	00010010	33	000001101011
34	00010011	34	000011010010
35	00010100	35	000011010011
36	00010101	36	000011010100
37	00010110	37	000011010101
38	00010111	38	000011010110
39	00101000	39	000011010111
40	00101001	40	000001101100
41	00101010	41	000001101101
42	00101011	42	000011011010
43	00101100	43	000011011011
44	00101101	44	000001010100
45	00000100	45	000001010101
46	00000101	46	000001010110
47	00001010	47	000001010111
48	00001011	48	000001100100
49	01010010	49	000001100101
50	01010011	50	000001010010
51	01010100	51	000001010011
52	01010101	52	000000100100
53	00100100	53	000000110111
54	00100101	54	000000111000
55	01011000	55	000000100111
56	01011001	56	000000101000
57	01011010	57	000001011000
58	01011011	58	000001011001
59	01001010	59	000000101011
60	01001011	60	000000101100
61	00110010	61	000001011010
62	00110011	62	000001100110
63	00110100	63	000001100111

Table 9.1.10.2: Make-up codes
(reproduced from ITU-T Recommendation T.4)

One run length	Code word	Zero run length	Code word
64	11011	64	0000001111
128	10010	128	000011001000
192	010111	192	000011001001
256	0110111	256	000001011011
320	00110110	320	000000110011
384	00110111	384	000000110100
448	01100100	448	000000110101
512	01100101	512	0000001101100
576	01101000	576	0000001101101
640	01100111	640	0000001001010
704	011001100	704	0000001001011
768	011001101	768	0000001001100
832	011010010	832	0000001001101
896	011010011	896	0000001110010
960	011010100	960	0000001110011

9.1.11 Segmentation of upper layer PDUs into RLC data units

Segmentation of upper layer PDUs is supported to allow transport of upper layer PDUs larger than the data field of a single RLC data block. If the contents of an upper layer PDU do not fill an integer number of RLC data blocks, the beginning of the next upper layer PDU shall be placed within the final RLC data block of the first upper layer PDU, with no padding or spacing between the end of the first upper layer PDU and the beginning of the next. If the final upper layer PDU in the TBF does not fill an integer number of RLC data blocks, filler octets shall be used to fill the remainder of the RLC data block.

The received (and segmented) upper layer PDUs shall be put into RLC data blocks in the same order as they are received from higher layers, except if resource reallocation for an uplink TBF is needed as described in sub-clause 8.1.1.1.2. A Block Sequence Number (BSN) is included in the header of each RLC data block to number the RLC data block. The RLC data blocks are to be numbered consecutively, modulo SNS, to allow re-assembly of the upper layer PDUs on the receiving side.

If EMSR is enabled, the transmission of an upper layer PDU may be suspended to transmit one or more upper layer PDUs of a higher priority. Once all higher priority upper layer PDUs have been transmitted, the transmission of the lower priority upper layer PDU can be resumed. The transition between two upper layer PDUs resulting from this suspend-resume function is described in sub-clause 10.4.14a.

In GPRS TBF mode, once an RLC data block has been transmitted over the physical link, should it be necessary to re-transmit the RLC data block, it shall be re-transmitted using the same channel coding scheme, BSN, and CV as it had in the previous transmission.

In EGPRS TBF mode, once an RLC data block has been transmitted over the physical link, should it be necessary to re-transmit the RLC data block, it shall be re-transmitted using the same BSN and the same calculated CV as were used in the previous transmission. The modulation and coding scheme may be changed following the procedures described in sub-clause 9.3.2.1.

In EC TBF mode, once an RLC data block has been transmitted over the physical link, should it be necessary to re-transmit the RLC data block, it shall be re-transmitted using the same BSN and the same CV as were used in the previous transmission. If the RLC data block is transmitted using blind physical layer transmissions, all the elements in the RLC/MAC header, except for the USF, shall be the same in the retransmission as were used in the previous transmission. Otherwise, the modulation and coding scheme may be changed following the procedures described in sub-clause 9.3.2.1a.

9.1.12 Re-assembly of upper layer PDUs from RLC data units

RLC data blocks shall be collected at the receiver until all RLC data blocks comprising an upper layer PDU have been received. The RLC headers shall be removed from each RLC data block at this time and the RLC data units re-assembled into an upper layer PDU and passed to the next higher layer. In A/Gb mode, the size of the upper layer PDU delivered to the higher layer shall not exceed 1560 octets. Any octet received beyond this maximum limit and until the next identified upper layer PDU boundary shall be discarded.

During RLC acknowledged mode operation, received upper layer PDUs shall be delivered to the higher layer in the order in which they were originally transmitted.

During RLC unacknowledged mode operation, received upper layer PDUs shall be delivered to the higher layer in the order in which they are received.

During RLC non-persistent mode operation, received upper layer PDUs shall be delivered to the higher layer in the order in which they were originally transmitted. Nevertheless, since some RLC data units may not be received, some upper layer PDUs may be re-assembled and delivered to the higher layer erroneously. The receiving RLC endpoint shall use RLC data units up to the one characterized by BSN = V(Q) – 1 when reassembling upper layer PDUs, even if some RLC data units are missing.

If EMSR is enabled, the transmission of an upper layer PDU may be suspended to transmit one or more upper layer PDUs of a higher priority and resumed thereafter. The transition between two upper layer PDUs resulting from this suspend-resume function is described in sub-clause 10.4.14a.

Fill bits having the value ‘0’ shall be substituted for RLC data units not received. However, in EGPRS TBF mode, for erroneous RLC data blocks for which the header is correctly received, the output from decoder shall be delivered to the higher layer. The number of fill bits substituted shall be determined using Tables 9.1.12.a, 9.1.12.b, 9.1.12.c, 9.1.12.d, 9.1.12.e, 9.1.12.f. In the uplink direction the channel coding scheme shall be the commanded channel coding scheme. In the downlink direction the channel coding scheme shall be the channel coding scheme of the last correctly received RLC data block. If no RLC data blocks have been correctly received, by the mobile station the requested channel coding scheme shall be used. If no requested channel coding scheme has been sent to the network, the mobile station shall use the number of fill bits for CS-1.

Table 9.1.12.a: RLC unacknowledged mode fill bits (GPRS)

Channel Coding Scheme	Number of fill bits
CS-1	160
CS-2	240
CS-3	288
CS-4	400

Table 9.1.12.b: RLC unacknowledged mode fill bits (EGPRS)

Channel Coding Scheme	Number of fill bits
MCS-1	176
MCS-2	224
MCS-3 with padding	248
MCS-3	296
MCS-4	352
MCS-5	448
MCS-6 with padding	544
MCS-6	592
MCS-7	448
MCS-8	544
MCS-9	592

Table 9.1.12.c: RLC unacknowledged mode fill bits (EGPRS2-A downlink)

Channel Coding Scheme	Number of fill bits
MCS-2 with padding	208
DAS-5	448
DAS-6	544
DAS-7	656
DAS-8	448
DAS-9	544
DAS-10	656
DAS-11	544
DAS-12	656

NOTE: MCS-1, MCS-2 (with or without padding), MCS-3 (with or without padding), MCS-4, MCS-6, MCS-7 and MCS-8 are also used for EGPRS2-A downlink (see sub-clause 5.2.1). For these modulation and coding schemes, fill bits are defined in Table 9.1.12.b unless specified otherwise.

Table 9.1.12.d: RLC unacknowledged mode fill bits (EGPRS2-B downlink)

Channel Coding Scheme	Number of fill bits
DBS-5	448
DBS-6	592
DBS-7	448
DAS-10 with padding	592
DBS-8	592
DBS-9	448
DAS-12 with padding	592
DBS-10	592
DBS-11	544
DBS-12	592

NOTE: MCS-1, MCS-2, MCS-3 (with or without padding), MCS-4, MCS-6 to MCS-9, DAS-5, DAS-6, DAS-8, DAS-9, DAS-10 with padding, DAS-11and DAS-12 with padding are also used for EGPRS2-B downlink (see sub-clause 5.2.1). For these modulation and coding schemes, fill bits are defined in Table 9.1.12.b and Table 9.1.12.c. unless specified otherwise.

Table 9.1.12.e: RLC unacknowledged mode fill bits (EGPRS2-A uplink)

Channel Coding Scheme	Number of fill bits
MCS-3 with padding	216
MCS-6 with padding	512
UAS-7	448
UAS-8	512
UAS-9	592
UAS-10	448
UAS-11	512

NOTE: MCS-1, MCS-2, MCS-3 (with or without padding), MCS-4, MCS-5 and MCS-6 (with or without padding) are also used for EGPRS2-A uplink (see sub-clause 5.2.1). For these modulation and coding schemes, fill bits are defined in Table 9.1.12.b unless specified otherwise.

Table 9.1.12.f: RLC unacknowledged mode fill bits (EGPRS2-B uplink)

Channel Coding Scheme	Number of fill bits
UBS-5	448
UBS-6 with padding	544
UBS-6	592
UBS-7	448
UBS-8 with padding	544
UBS-8	592
UBS-9	448
UBS-10 with padding	544
UBS-10	592
UBS-11	544
UBS-12	592

NOTE: MCS-1 to MCS-4 are also used for EGPRS2-B uplink (see sub-clause 5.2.1). For these modulation and coding schemes, fill bits are defined in Table 9.1.12.b unless specified otherwise.

9.1.12a Segmentation of RLC/MAC control messages into RLC/MAC control blocks

The network may segment RLC/MAC control messages into one, two or up to nine RLC/MAC control blocks depending on the length of the RLC/MAC control message. Segmentation of an RLC/MAC control message into more than two RLC/MAC control blocks is referred to as extended RLC/MAC control message segmentation. Extended RLC/MAC control message segmentation shall not be used for an RLC/MAC control message that can be sent using one or two RLC/MAC control blocks. Unless explicitly stated otherwise, extended RLC/MAC control message segmentation shall not be used. If the contents of a control message do not fit an integer number of control blocks, filler octets shall be used to fill the remainder of the RLC/MAC control block. Only the last RLC/MAC control block containing elements of the control message shall contain filler octets. The Final Segment (FS) bit of the RLC/MAC control block header shall be set according to whether the RLC/MAC control block contains the final segment of an RLC/MAC control message, except in case of extended RLC/MAC control message segmentation in which case the FS bit shall always be set to ‘0’. In case of extended RLC/MAC control message segmentation, the Final Segment extension (FSe) bit of the RLC/MAC control block header (included in the second RLC/MAC control block onwards) shall be set according to whether the RLC/MAC control block contains the final segment of an RLC/MAC control message (see sub-clauses 10.4.9e and 10.4.12b).

The mobile station shall not segment RLC/MAC control messages.

NOTE: In order to provide the mobile station a Power Reduction value in a RLC/MAC control block, the network may use the segmentation mechanism although the RLC/MAC control block requires only one RLC/MAC control block to be transmitted. In that case the RBSN shall be set to ‘0’ and FS shall be set to ‘1’.

9.1.12b Re-assembly of RLC/MAC control messages from RLC/MAC control blocks

RLC/MAC control blocks shall be collected at the receiver until all RLC/MAC control blocks comprising an RLC/MAC control message have been received.

In packet idle mode, the mobile station shall be capable of receiving eight RLC/MAC control messages in parallel. If the mobile station receives RLC/MAC control blocks containing part of a ninth RLC/MAC control message while it still has RLC/MAC control blocks for eight partially received RLC/MAC control messages, the mobile station shall discard the RLC/MAC control blocks of the oldest partially received message.

A mobile station that has enabled EC operation only needs to be capable of receiving one RLC/MAC control message at a time when in packet idle mode.

In packet transfer mode, the mobile station shall be capable of receiving two RLC/MAC control messages in parallel on the same PDCH. If the mobile station receives RLC/MAC control blocks containing part of a third RLC/MAC control message while it still has RLC/MAC control blocks for two partially received RLC/MAC control messages, the mobile station shall discard the RLC/MAC control block of the oldest partially received message.

A mobile station in EC operation only needs to be capable of receiving one RLC/MAC control message at a time when in packet transfer mode, i.e. when it has an EC TBF.

A mobile station, which is not in EC operation, shall start an instance of timer T3200 following the receipt of an RLC/MAC control block whose RTI value does not correspond to the RTI value of a partially received RLC/MAC control message or if the RLC/MAC control blocks were received on different PDCHs. In non-DRX mode the duration of timer T3200 shall be four BS_CV_MAX block periods. In DRX mode the duration of timer T3200 shall be four times the DRX period (see 3GPP TS 43.064).

A mobile station in EC operation shall start timer T3200 following the receipt of an RLC/MAC control block containing a segment of an RLC/MAC control message such that the mobile station still does not have the complete RLC/MAC control message.

On receipt of an RLC/MAC control block containing a segment of an RLC/MAC control message such that the mobile station still does not have the complete RLC/MAC control message, the mobile station shall restart the corresponding instance of timer T3200.

On receipt of an RLC/MAC control block containing a segment of an RLC/MAC control message such that the mobile station now has the complete RLC/MAC control message, the mobile station shall stop the corresponding instance of timer T3200.

If the mobile station discards a partially received RLC/MAC control message while the corresponding instance of timer T3200 is running, the mobile station shall stop the corresponding instance of timer T3200.

On expiry of an instance of timer T3200, the mobile station shall discard and ignore all segments of the corresponding partially received RLC/MAC control message.

Upon successful change of PDCH allocation, the mobile station shall discard all partially received RLC/MAC control messages and stop the corresponding instances of timer T3200.

The mobile station shall discard any control message segment that contains an unknown TFI.

9.1.13 Priority of upper layer PDUs

The mobile station shall not transmit upper layer PDUs during a TBF that have a lower Radio Priority than the priority that was used at initial access or the priority sent in the last PACKET RESOURCE REQUEST message, except if the upper layer PDUs at the higher Radio Priority does not completely fill the RLC data block (see sub-clause 8.1.1.1.2). The mobile station may change the Radio Priority of an uplink TBF by sending a PACKET RESOURCE REQUEST message to the network (see sub-clause 8.1.1.1.2).

9.1.14 Fast Ack/Nack Reporting

9.1.14.1 General

The Fast Ack/Nack reporting procedure (FANR) allows to piggy-back, within EGPRS RLC/MAC blocks for data transfer sent in one direction, the acknowledgement status of data blocks relative to a TBF in the opposite direction. The acknowledgement status is provided with a Piggy-backed Ack/Nack (PAN) field of which the presence within an EGPRS RLC/MAC block for data transfer is indicated with the PANI field within the RLC/MAC header of that block, see sub-clause 10.4.21.

The activation of FANR for a given TBF is signalled by the network at TBF establishment/reconfiguration. The mobile station shall proceed as follows:

– If a downlink TBF is established or reconfigured with FANR activated (see sub-clauses 11.2.7, 11.2.7a, 11.2.31, and 11.2.31a), the mobile station shall act upon sub-clauses 9.1.14.2 and 9.1.14.3. The mobile station shall always use the SSN-based encoding defined in subclause 9.1.8 to encode the PAN field.The RLC data blocks pertaining to a downlink TBF for which FANR is activated shall always be encoded using the relevant RLC/MAC header form specified in sub-clause 10.3a.3 (i.e. PANI and CES/P fields present) irrespective of the existence of a concurrent TBF in the uplink direction.

– If an uplink TBF is established or reconfigured with FANR activated (see sub-clauses 11.2.29, 11.2.29a, 11.2.31, and 11.2.31a), the mobile station shall monitor for the presence of a PAN field for this TBF on all downlink PDCHs on which it shall monitor the USF for this TBF. The mobile station shall only attempt to decode a PAN field in a downlink EGPRS RLC/MAC block for data transfer if it is already required to check for a USF within that RLC/MAC block. If the presence of a PAN field is indicated in the header of an EGPRS RLC/MAC block for data transfer received on these PDCHs, the mobile station shall attempt to decode the PAN field also in the blocks addressed to other mobile stations. The network may encode the PAN field according to the SSN-based encoding defined in subclause 9.1.8 or the time-based encoding defined in subclause 9.1.15. The specific encoding selected by the network is notified to the mobile station at TBF establishment/reconfiguration (see sub-clauses 11.2.29, 11.2.29a, 11.2.31, and 11.2.31a) and, if multiple TBFs procedures are supported, it shall be the same for all the uplink TBF of the same mobile station. The decision for transmitting a PAN field by the network is implementation specific.

– If the PAN is addressed to a different mobile station than the one to which the data in the RLC/MAC block carrying the PAN is addressed, the same restrictions for the network’s selection of the modulation and coding scheme apply as for the USF transmission to this MS, see sub-clause 5.2.4a (except for MCS-4 and MCS-9 which cannot carry a PAN).

NOTE 1: FANR is supported only on full-rate PDCH and PDCH-pair.

NOTE 2: If the network does not have any EGPRS RLC/MAC blocks for data transfer in downlink direction but a downlink PAN field is available for transmission to a mobile station operating in A/Gb mode, the network may use an LLC UI Dummy command (see 3GPP TS 44.064) to create an EGPRS RLC/MAC data block where the PAN field available for transmission can be sent.

NOTE 3: FANR can be activated for a TBF operated in RLC unacknowledged mode.

The network shall activate FANR for any assigned TBF which uses an RTTI or MTTI configuration.

9.1.14.2 Polled Fast Ack/Nack Reporting

Polled FANR may be used together with event-based FANR (see sub-clause 9.1.14.3).

If the RLC endpoint transmitter is the network and the mobile station has at least one concurrent TBF in the uplink direction, the network may poll the mobile station to trigger the FANR procedure. In this case the mobile station shall answer in a reserved radio block period which is allocated with the polling as described in sub-clause 8.1.2.2.

In the case where the network polls for a PAN and the mobile station does not transmit a PAN (e.g. because it does not have any EGPRS RLC/MAC blocks for data transfer in the uplink direction, all the elements of V(B) have the value TENTATIVE_ACK or ACKED, does not have any TBF assigned in the uplink direction or does not have an uplink TBF that has been assigned a PDCH corresponding to the downlink PDCH where the poll was received or a PDCH-pair corresponding to the downlink PDCH-pair where the poll was received), the mobile station shall transmit an EGPRS PACKET DOWNLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK TYPE 2, EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC message containing NPB, see sub-clause 10.4.4b.

9.1.14.3 Event-based Fast Ack/Nack Reporting

Event-based FANR may be used together with Polled FANR (see sub-clause 9.1.14.2).

If the RLC endpoint receiver is the mobile station, event-based FANR is enabled for this TBF and the mobile station has at least one assigned TBF in the uplink direction, the mobile station shall insert one PAN field in an EGPRS RLC/MAC block for data transfer transmitted during a given radio block period for that uplink TBF if the state of any element in the receive state array V(N) is UNREPORTED and that element will not otherwise be reported (e.g. in response to a poll) during the radio block period. In addition, the mobile station may insert one PAN field in an EGPRS RLC/MAC block for data transfer transmitted during a given radio block period even if that element will be reported in response to a poll during the radio block period.

The mobile station may continue to insert PAN fields in subsequent EGPRS RLC/MAC data blocks sent in the same radio block period as long as there exists one or more elements in the receive state array V(N) whose state is UNREPORTED.

If event-based FANR is enabled and the network polls the mobile station, the mobile station shall transmit, in the reserved radio block period which is allocated with the polling, one of the messages as described in sub-clause 8.1.2.2.

If the mobile station does not have any RLC data block waiting for the transmission, the mobile station shall transmit an EGPRS PACKET DOWNLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK TYPE 2, EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC message containing NPB.

In case of multiple-TBF allocation or if multiple RLC entities are multiplexed within a single TBF by means of EMST, a mobile station shall insert a PAN field indicating unreported erroneous RLC data blocks from TBFs, or in case of EMST, from an RLC entity in RLC non-persistent mode prior to a PAN field indicating unreported erroneous RLC data blocks from TBFs, or in case of EMST, from an RLC entity in RLC acknowledged mode.

9.1.15 Time-based encoding of the Piggy-backed Ack/Nack field

9.1.15.1 Generation of the bitmap

When the time-based encoding is used (see sub-clause 9.1.14.1), the Piggy-backed Ack/Nack (PAN) field included in a radio block transmitted by the network in a given basic (respectively reduced) radio block period shall contain a bitmap providing feedback information relative to the reception of radio blocks in basic (respectively reduced) TTI configuration at the network side, possibly from different mobile stations, in the previous basic (respectively reduced) radio block periods on a number of uplink PDCHs (respectively PDCH-pairs).

The network shall indicate at TBF establishment/reconfiguration (see sub-clauses 11.2.29, 11.2.29a, 11.2.31, and 11.2.31a) the timeslots for which feedback is provided and the time-shift TSH (expressed in number of TDMA frames) between the most recent radio block period for which feedback information is provided and the radio block period when the bitmap is sent. If the TBF operates in RTTI configuration or MTTI configuration, feedback shall be provided for an even number of timeslots (see sub-clause 12.18).

A variable number (between 1 and 3) of bits are used in the PAN field to notify the status of every reported radio block, as described in Table 9.1.15.1.1. For modulation and coding schemes where two RLC data blocks are transmitted within a single radio block, there is one RLC data block per "RLC data block group". For modulation and coding schemes where three RLC data blocks are transmitted within a single radio block, the first "RLC data block group" contains the first RLC data block and the second "RLC data block group" contains the second and third RLC data blocks. For modulation and coding schemes where four RLC data blocks are transmitted within a single radio block, the first "RLC data block group" contains the first two RLC data blocks and the second "RLC data block group" contains the third and fourth RLC data blocks. An RLC data block group containing two RLC data blocks shall be indicated as having been successfully decoded only if both constituent RLC data blocks have been successfully decoded.

Table 9.1.15.1.1: Feedback information for every reported radio block

Bit string	Meaning (radio block contains one RLC block)	Meaning (radio block contains two or more RLC blocks)
0 1 0	failed header decoding	– failed header decoding – header correctly received but failed decoding of the payload of both RLC data block groups
0 0	header correctly received but failed decoding of the payload of the RLC data block	header correctly received, successful decoding of the first RLC data block group, failed decoding of the second RLC data block group
0 1 1	reserved	header correctly received, successful decoding of the second RLC data block group, failed decoding of the first RLC data block group
1	header correctly received and successful decoding of the payload of the RLC data block	header correctly received and successful decoding of the payload of both RLC data block groups

For a PAN field transmitted in a given basic (respectively reduced) radio block starting with TDMA frame N, the first code in the bitmap shall refer to the radio block received on the first reported uplink PDCH (respectively PDCH-pair) starting with TDMA frame (N-TSH or N-TSH-1) mod 2715648, the second code shall refer to the radio block received on the second reported uplink PDCH (respectively PDCH-pair) starting with TDMA frame (N-TSH or N-TSH-1) mod 2715648, etc. If there is still space in the PAN field, then the next code shall refer to the radio block received on the first reported uplink PDCH (respectively PDCH-pair) starting with TDMA frame (N-TSH-4 or N-TSH-5) mod 2715648 for TBFs in basic TTI configuration (respectively TDMA frame (N-TSH-2 or N-TSH-3) mod 2715648 for TBFs in reduced TTI configuration) and so on.

In a PAN field included in a radio block transmitted in basic (respectively reduced) TTI configuration, the network shall include a bit string as specified in Table 9.1.15.1.1 for every PDCH (respectively PDCH-pair) covered by the report, even if no uplink radio block in basic (respectively reduced) TTI configuration was scheduled to be transmitted on that PDCH/PDCH-pair.

NOTE: For a PAN field included in a radio block transmitted in basic (respectively reduced) TTI configuration, bit strings shall be included in the positions corresponding to PDCHs (respectively PDCH-pairs) on which radio blocks in reduced (respectively basic) TTI configuration were scheduled.

In the case of a PAN field received within an RTTI block by a mobile station with an uplink MTTI configuration (see sub-clause 7.1.3.7) and which covers both the PDCH and one or more PDCH-pairs for that MTTI configuration, the network shall include the applicable bit string for the BTTI radio block in the first of the two positions which would otherwise be used for reporting the status of two uplink RTTI radio blocks sent using a PDCH-pair that includes that PDCH.

In the case of a PAN field received within a BTTI block by a mobile station with an uplink MTTI configuration (see sub-clause 7.1.3.7) and which covers both the PDCH and one or more PDCH-pairs for that MTTI configuration, the network shall include the applicable bit string for the later (respectively earlier) RTTI radio block in the first (respectively second) of the two positions which would otherwise be used for reporting the status of two uplink BTTI radio blocks sent using the PDCHs that comprise the PDCH-pair being reported.

If necessary, the PAN field may be padded using either one or two bits. If one bit of padding is required, then a ‘0’ shall be used. If two bits is required, the bit string ‘0 1’ shall be used.

9.1.15.2 Interpretation of the bitmap

If the time-based encoding is used, when a mobile station successfully decodes a PAN field in a radio block transmitted in basic (respectively reduced) TTI configuration it correlates the received feedback information, which may refer to the transmission of different mobile stations, with the knowledge of the RLC data blocks (i.e. the BSNs) it transmitted in a given basic (respectively reduced) radio block period on a given uplink PDCH (respectively PDCH-pair) during the time window covered by the PAN field. The mobile station shall then derive which RLC data blocks were correctly received or not by the network in that time window. In case of multiple TBFs in different TTI configurations the mobile station shall not derive any information for TBFs in basic (respectively reduced) TTI configuration from PAN fields included in radio blocks transmitted in reduced (respectively basic) TTI configuration. A mobile station assigned uplink resources in an MTTI configuration (see sub-clause 7.1.3.7) shall derive information for both RTTI radio blocks and BTTI radio blocks which are covered by the PAN field (see sub-clause 9.1.15.1).

If the final bit(s) in the bitmap do not correspond to any valid bitstring as specified in sub-clause 9.1.15.1, these bits shall be ignored.

Where it is indicated that the decoding of an RLC data block group failed, and that RLC data block group contained two RLC data blocks, then the mobile station shall consider that the decoding of both RLC data blocks failed.

For the RLC data blocks correctly received the corresponding elements in V(B) shall be set to the value ACKED.

For each RLC data block not correctly received the corresponding element in V(B) shall be set to the value NACKED, if the number of basic (respectively reduced) radio block periods between the end of the radio block period used for the last transmission of the corresponding RLC data block and the beginning of the radio block period containing the PAN field is higher or equal than (TSH/4)-1 for TBFs in basic TTI configuration (respectively (TSH/2)-1 for TBFs in reduced TTI configuration), i.e. the RLC data block was not recently (re)transmitted and thus can be validly negatively acknowledged by this particular PAN field, otherwise the corresponding element in V(B) shall not be modified.

9.2 Operation during RLC/MAC control message transfer

RLC/MAC control blocks shall be used to transport RLC/MAC control messages. Segments of only one RLC/MAC control message shall be transported per RLC/MAC control block.

RLC/MAC control blocks shall be sent at a higher priority than RLC data blocks.

The receiving side shall determine the length of the RLC/MAC control message contents by interpreting the RLC/MAC control block contents.

No general acknowledgement shall be made as part of the transfer of RLC/MAC control blocks or RLC/MAC control messages. The receiver shall not acknowledge an RLC/MAC control block except when a valid RRBP field is present in the MAC header of the RLC/MAC control block. The receiver shall not acknowledge an RLC/MAC control message except when the RLC/MAC procedures explicitly specify an acknowledgement.

Each downlink RLC/MAC control block header, if present, contains a Radio Transaction Identifier (RTI) field that is 5 bits in length and performs in effect a modulo 32 count of the downlink RLC/MAC control messages sent on a PDCH. The RTI field shall be used to group the RLC/MAC control blocks that make up an RLC/MAC control message. The RTI field allows the transmitting and receiving entities to distinguish between up to 32 RLC/MAC control messages in a single transmit direction therefore allowing up to 32 parallel transactions per PDCH.

The network shall not use the same RTI value at the same time on the same PDCH for two separate RLC/MAC control messages. The network may use the same RTI value at the same time on separate PDCHs. The network shall transmit all segments of a segmented control message on the same PDCH.

9.3 Operation during RLC data block transfer

9.3.0 General

The RLC ARQ functions support three modes of operation: RLC acknowledged mode, RLC unacknowledged mode and RLC non-persistent mode. RLC acknowledged mode operation uses retransmission of RLC data blocks to achieve high reliability. RLC unacknowledged mode operation does not utilize retransmission of RLC data blocks. RLC non-persistent mode operation uses non-exhaustive retransmission of RLC data blocks. A TBF may operate in either RLC acknowledged mode, RLC unacknowledged mode or RLC non-persistent mode. An MBMS bearer operates in RLC non-persistent mode. An EC TBF operates in RLC acknowledged mode.

A mobile station, which has not enabled EC operation, requests the RLC mode of the uplink TBF by setting the RLC_MODE bit to either RLC acknowledged mode or RLC unacknowledged mode in the PACKET RESOURCE REQUEST or the (EGPRS) PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or the EGPRS PACKET DOWNLINK ACK/NACK DLMC message. When the establishment cause field in the PACKET CHANNEL REQUEST message indicates ‘one phase access’, the RLC mode defaults to RLC acknowledged mode. If both the mobile station and the BSS support multiple TBF procedures, or if the mobile station supports RLC non-persistent mode, the BSS may override the mobile station’s indicated RLC mode, ordering its preferred RLC mode (including RLC non-persistent mode for EGPRS TBF(s), if the mobile station supports this RLC mode) when establishing uplink TBF(s) as follows:

– The network shall always set the RLC_MODE bit for the uplink TBF(s) in the MULTIPLE TBF UPLINK ASSIGNMENT and MULTIPLE TBF TIMESLOT RECONFIGURE messages.

– The network may order the RLC mode for the uplink TBF by setting the RLC_MODE bit in the PACKET UPLINK ASSIGNMENT message or the UPLINK_RLC_MODE bit in the PACKET TIMESLOT RECONFIGURE message. The mobile station shall assume that its indicated RLC mode is used if the BSS does not override it in the PACKET UPLINK ASSIGNMENT or PACKET TIMESLOT RECONFIGURE message.

The network sets the RLC mode of the downlink TBF by setting the RLC_MODE bit in the PACKET DOWNLINK ASSIGNMENT, MULTIPLE TBF DOWNLINK ASSIGNMENT, PACKET TIMESLOT RECONFIGURE, MULTIPLE TBF TIMESLOT RECONFIGURE or PACKET CS RELEASE INDICATION message.

An uplink TBF may be operating in either non-extended uplink TBF mode or extended uplink TBF mode, see sub-clause 9.3.1b. An uplink TBF operating in RLC non-persistent mode shall operate in extended uplink TBF mode.

The extended uplink TBF mode is not applicable for an uplink EC TBF. The use of the Countdown Value (CV) is instead optional in an uplink EC TBF and it may be used to prolong the TBF, see sub-clause 9.3.1.4. The CV shall however always be included for the last uplink RLC data block of the uplink EC TBF.

When one or more PDCH/Fs are used in conjunction with one PDCH/H in the same direction, the RLC/MAC data blocks may not be received in the same sequence they were sent, due to the different data rates of the channels. In RLC unacknowledged mode, the sending entity shall re-order the RLC/MAC data blocks before transmission to ensure their reception in sequence.

9.3.1 Countdown procedure

9.3.1.1 General

The mobile station shall send the Countdown Value (CV) in each uplink RLC data block to indicate the current number of remaining RLC data blocks for the uplink TBF, except for an uplink EC TBF. In case EMST is used, the CV shall indicate the current number of remaining RLC data blocks for the corresponding RLC entity allocated to the uplink TBF.

A mobile station with an uplink EC TBF is only required to send the Countdown Value (CV) in an uplink RLC data block in order to inform the network that there are more remaining RLC data blocks for the uplink TBF than it has previously signalled to the network. The mobile station is also required to send the CV in the last uplink RLC data block of the TBF. The Follow-On Indication (FOI) shall then be set to ‘1’ to indicate the presence of the CV.

The CV for a non EC TBF shall be calculated as follows:

where:

TBC = total number of RLC data blocks currently to be transmitted in the TBF.

BSN’ = absolute block sequence number of the RLC data block, with range from 0 to (TBC – 1).

NTS = number of timeslots assigned to the uplink TBF in the assignment message, with range 1 to 8 when operating in BTTI configuration. In RTTI configuration this parameter shall be equal to the number of assigned uplink PDCH pairs, with the range 1 to 4. In an MTTI configuration, the parameter shall be equal to the number of uplink BTTI PDCHs assigned plus twice the number of RTTI PDCH-pairs assigned, with the range 3 to 7.

K = 2 when commanded MCS is MCS-7, MCS-8, MCS-9, UAS-7, UAS-8, UAS-9, UBS-7 or UBS-8
3 when commanded UAS-10, UAS-11, UBS-9 or UBS-10
4 when commanded UBS-11 or UBS-12 otherwise K=1,
the function round() rounds upwards to the nearest integer.

BS_CV_MAX is a parameter broadcast in the system information,
the division operation is non-integer and results in zero only for (TBC – BSN’ – 1) = 0.

The CV for an uplink EC TBF is calculated as follows:

where:

TBC = total number of RLC data blocks currently to be transmitted in the TBF.

BSN’ = absolute block sequence number of the RLC data block, with range from 0 to (TBC – 1).

K = 2 when commanded MCS is MCS-7, MCS-8 or MCS-9
otherwise K=1,
the function round() rounds upwards to the nearest integer.

The countdown procedure, for a non EC TBF, starts when RLC data blocks include CV values different from ’15’. When the mobile station transmits the last RLC data block currently in the send buffer for the TBF (i.e. the RLC data block with BSN’ = TBC – 1), the RLC data block shall have CV set to the value ‘0’.

When an EGPRS, EGPRS2 or EC-GSM-IoT RLC/MAC block for data transfer consists of two or more RLC data blocks, a CV value is calculated for each block and the CV of the RLC/MAC header refers to the last RLC data block.

9.3.1.2 Non-extended uplink TBF mode

In an uplink TBF operating in non-extended uplink TBF mode, the CV shall indicate the absolute BSN (BSN’) of the last RLC data block that will be sent in the uplink TBF. The TBC value is the total number of RLC data blocks that will be transmitted in the TBF.

At the point in time the mobile station having an uplink TBF in non-extended TBF mode transmits the first RLC data block indicating a CV other than 15, the mobile station shall transmit afterwards exactly (TBC ‑ BSN’ ‑ 1) untransmitted RLC data blocks.

If the mobile station receives a change in the Channel Coding Command in a PACKET UPLINK ACK/NACK message during the countdown procedure, the mobile station shall act upon the new Channel Coding Command. The mobile station shall then recalculate the CV for any untransmitted RLC data block using the new RLC data block size.

If the mobile station successfully completes the contention resolution procedure during one phase access and the countdown procedure is already running,, the mobile station shall recalculate the CV for any untransmitted RLC data blocks.

Any data that arrives from the higher layer after the commencement of the countdown process shall be sent within a future TBF.

The mobile station may retransmit during the countdown in response to a Packet Ack/Nack or if stalled.

If the mobile station receives a new allocation during the countdown, the mobile station shall use this new allocation to the end of the countdown procedure. The network shall provide unsolicited uplink resources for any retransmissions that may be required.

9.3.1.3 Extended uplink TBF mode

In an uplink TBF operating in extended uplink TBF mode, the CV shall indicate the current number of RLC data blocks that has not been transmitted in the uplink TBF. The mobile station shall update the TBC value and recalculate the CV for any untransmitted RLC data block in the following cases:

– The RLC entity of the mobile station receives new data from upper layers for transmission in the uplink TBF.

– The mobile station completes the contention resolution at one-phase packet access.

– The mobile station changes the coding scheme of the RLC data blocks transmitted in an uplink TBF operating in GPRS TBF mode.

– The mobile station changes the modulation and coding scheme of the RLC data blocks transmitted in an uplink TBF operating in EGPRS TBF mode.

NOTE: Updating the TBC value shall not result in changing the CV of the RLC data blocks already transmitted, in the case they need to be retransmitted.

9.3.1.4 End of uplink EC TBF

An uplink EC TBF is released when the network has received all RLC data blocks for a TBF, as indicated by the mobile station, and sent the EC PACKET UPLINK ACK/NACK message with the Final Ack Indicator bit set to ‘1’. An exception is when the mobile station, in the EC PACKET UPLINK ACK/NACK message with the Final Ack Indicator bit set to ‘1’, is ordered to continue monitoring the EC-PACCH, see sub-clause 9.3.2.4.3.

The end of the uplink TBF is indicated by the mobile station by inclusion of a block count indicating a specific number data blocks to be sent for the TBF in the EC Packet Channel Request message or by inclusion of the Countdown Value (CV) in the RLC/MAC header of one or several of the uplink RLC data blocks that are sent within the TBF. The mobile station indicates the presence of a valid CV field in the RLC/MAC header by setting the FOI field to ‘1’. The end of the uplink EC TBF, i.e. the absolute BSN (BSN’) of the last RLC data block that will be sent in the TBF, shall be indicated by the mobile station by including the CV field in the first possible uplink RLC data block to be transmitted, in case the EC Packet Channel Request message did not indicate a specific number data blocks to be sent. The CV field shall be included, set to the value ´0´, in the last RLC data block of the TBF.

The mobile station may prolong the uplink TBF by including a CV that indicates a later end of the TBF than previously indicated, unless CV=0 has already been indicated in an uplink RLC data block. If the network receives several uplink RLC data blocks with CV pointing at different end points for the TBF, the CV of the newest uplink RLC data block, i.e. with the highest absolute BSN (BSN’), shall be considered valid.

In case the end of the uplink TBF, i.e. the absolute BSN (BSN’) of the last RLC data block that will be sent in the TBF, is changed compared to the most recent indication, e.g. due to that a different Modulation and Coding Scheme (MCS) than previously used has been commanded for the TBF, the mobile station shall include the CV at the first possible occasion to indicate the end of the TBF.

If the mobile station receives a change in the Channel Coding Command in an EC PACKET UPLINK ACK/NACK message, the mobile station shall act upon the new Channel Coding Command and recalculate the CV for any untransmitted RLC data block using the new RLC data block size.

If the mobile station successfully completes the contention resolution procedure and the end of the uplink TBF has already been indicated to the network, as an absolute BSN (BSN’) of the last RLC data block that will be sent in the TBF, the mobile station shall recalculate the CV for any untransmitted RLC data blocks.

9.3.1a Delayed release of downlink Temporary Block Flow

When the network exhausts its supply of downlink data for a downlink TBF, it may release the TBF by using one of the procedures in sub-clause 9.3.2.6 or sub-clause 9.3.3.5. If a TBF is not instantly released, the network may continue the downlink TBF awaiting new data to be received from the upper layers. After a period of inactivity, the TBF shall be released at a point determined by the network, using one of the procedures in sub-clause 9.3.2.6, sub-clause 9.3.3.5 or sub-clause 8.1.2.8. Once the release of a downlink TBF is initiated, the TBF shall not be continued.

If the network continues a downlink TBF when the supply of downlink data is exhausted, the RLC entity on the network side shall insert filler information into the RLC data blocks that are transmitted to the mobile station. For a mobile station operating in A/Gb mode, this is achieved by the insertion of LLC UI Dummy commands (see 3GPP TS 44.064) into the TBF. For a mobile station operating in Iu mode, the network may directly transmit RLC data blocks with filler information by setting the LI field as described in sub-clauses 10.4.14 and 10.4.14a. The FBI bit in the RLC header shall be set to the value ‘0’ unless the network releases the TBF, in which case the FBI bit shall be set to the value 1.

If new data is received from the upper layers, the network stops sending filler information and resumes normal operation during RLC data block transfer.

RLC data blocks shall be sent to the mobile station as required to prevent the expiry of timer T3190 for each TBF, according to power control requirements, and as needed to poll the mobile station for the provision of (EC-)PACCH uplink blocks.

NOTE: Extensive delay of a downlink TBF release might impact badly on the mobile station power consumption and should be avoided. Inactivity periods should not be longer than necessary to keep the overall performance of GPRS services. Inactivity periods longer than 5 s should not be used unless the DTR mode is used, see sub-clause 8.1.8.

9.3.1b Extended uplink TBF mode

9.3.1b.1 Application

Network support of the extended uplink TBF mode shall be indicated by the NW_EXT_UTBF parameter that is broadcast on either BCCH or PBCCH, see sub-clause 12.24. A network which supports RLC non-persistent mode shall support extended uplink TBF mode. A network which supports Enhanced Flexible Timeslot Assignment, EFTA, shall support extended uplink TBF mode.

The mobile station shall support the extended uplink TBF mode. The extended uplink TBF mode is a part of the GERAN Feature Package 1. A mobile station indicating support of GERAN Feature Package 1 in the Mobile Station Classmark 3 IE, the MS Radio Access Capability IE and the MS Radio Access Capability 2 IE supports the extended uplink TBF mode (see 3GPP TS 24.008).

Extended uplink TBF mode is not supported in EC-GSM-IoT.

The RLC/MAC entity, which has received the indication that the peer supports the extended uplink TBF mode, shall operate an uplink TBF in the extended uplink TBF mode.

NOTE: The network might not receive the radio access capabilities of the mobile station at one-phase packet access. In that case, the two entities may operate in different mode.

9.3.1b.2 Operation of uplink TBF in extended uplink TBF mode

In extended uplink TBF mode, an uplink TBF may be maintained during temporary inactive periods, where the mobile station has no RLC information to send.

During the temporary inactive periods, the mobile station may stop sending RLC data block, as defined in sub-clause 9.1.3. The network shall continue allocating the mobile station uplink radio blocks during the inactivity period, using the procedures defined in sub-clause 8.1.1 for each medium access mode. Uplink radio blocks shall be allocated as required allowing the mobile station to continue the transfer of RLC data blocks, when a new RLC data block becomes available.

When the mobile station is allocated an uplink radio block and there is no RLC data block ready to send for any TBF, the mobile station shall send an RLC/MAC control block in each uplink radio block allocated by the network, unless indicated otherwise. When the mobile station is allocated an uplink radio block, and there is no RLC/MAC block for data transfer to send for this TBF but, in case of multiple TBFs, there is an RLC/MAC block for data transfer to send for one or more other TBF(s) assigned on the same PDCH, the mobile station should send an RLC/MAC block for data transfer from one of these other TBF(s) in the allocated uplink radio block indicating the TFI of that other TBF in the RLC/MAC header of that RLC/MAC block. The priorities defined in sub-clause 8.1.1 for different kinds of RLC/MAC blocks apply. The network may allow, via the EXT_UTBF_NODATA parameter broadcast in GPRS Cell Options IE (see sub-clause 12.24), any mobile station during extended uplink TBF mode not to send any PACKET UPLINK DUMMY CONTROL BLOCK message when there is no other RLC/MAC block ready to send. A mobile station during extended uplink TBF mode may refrain from sending PACKET UPLINK DUMMY CONTROL BLOCK messages when there is no other RLC/MAC block ready to send only if so indicated by the EXT_UTBF_NODATA parameter.

During a period when the network does not receive any RLC data blocks from the mobile station, the network may periodically send a PACKET UPLINK ACK/NACK message to the mobile station. When applicable, depending on the medium access mode, the PACKET UPLINK ACK/NACK message shall be sent as required to prevent timer T3184 from expiring.

The network determines the release of an uplink TBF. The network releases an uplink TBF using the procedure in sub-clause 9.5 (A/Gb mode).

NOTE 1: An uplink TBF may be released also by procedures defined in clause 8.

NOTE 2: Extensive delay of an uplink TBF release whilst the mobile station does not send any RLC information might impact badly on the mobile station power consumption and should be avoided. Inactivity periods should not be longer than necessary to keep the overall performance of GPRS services. Inactivity periods longer than 5 s should not be allowed unless the DTR mode is used, see sub-clause 8.1.8. If, however, the network has indicated that the mobile station during extended uplink TBF mode is not required to send PACKET UPLINK DUMMY CONTROL BLOCK messages, as described above, and the mobile station makes use of this option, the impact on the mobile station power consumption will be less critical and longer inactivity periods than 5 seconds can be allowed.

NOTE 3: Enhanched Flexible Timeslot Assignment, EFTA, is applicable only if the network has indicated that the mobile station during extended uplink TBF mode is not required to send PACKET UPLINK DUMMY CONTROL BLOCK messages as described above.

9.3.2 Acknowledged mode operation

9.3.2.0 General

The transfer of RLC data blocks in the RLC acknowledged mode uses retransmissions of RLC data blocks. The transmitting side numbers the RLC data blocks via the block sequence number (BSN). The BSN is used for retransmission and for reassembly. The receiving side sends Packet Ack/Nack messages in order to request retransmission of RLC data blocks.

9.3.2.1 Additional functionality in acknowledged EGPRS TBF Mode

In EGPRS TBF mode, the transfer of RLC Data Blocks in the acknowledged RLC/MAC mode may be controlled by a selective type I ARQ mechanism, or by type II hybrid ARQ (Incremental Redundancy: IR) mechanism, coupled with the numbering of the RLC Data Blocks within one Temporary Block Flow.

According to the link quality, an initial Modulation and Coding Scheme (MCS) is selected for an RLC block (see note). For the retransmissions, the same or another MCS from the same family of MCSs may be selected. E.g. if MCS-7 is selected for the first transmission of an RLC block, any MCS of the family B may be used for the retransmissions. Further, RLC data blocks initially transmitted with any MCS other than MCS-1, MCS-2 or MCS-3, may be retransmitted with MCS-1, MCS-2 or MCS-3 as appropriate, by sending the different parts of the RLC data block in different radio blocks. In this case, the SPB field in the header shall be set to indicate that the RLC data block is split, and which part of the RLC data block is retransmitted in the radio block.

For blocks initially transmitted with MCS-8 which are retransmitted using MCS-6 or MCS-3, for blocks initially transmitted with DAS-6, DAS-9, DAS-11 or DBS-11 which are retransmitted using MCS-3 and for blocks initially transmitted with UBS-11 which are retransmitted using UBS-10, UBS-8, UBS-6 or MCS-3, padding with all zeroes of the first six octets shall be applied. For blocks initially transmitted with UAS-8 or UAS-11 which are retransmitted using MCS-6 or MCS-3, padding with all zeroes of the first ten octets shall be applied. For blocks initially transmitted with DAS-7, DAS-10 or DAS-12 which are retransmitted using MCS-2, padding with all zeroes of the first two octets shall be applied. In all of these cases, the CPS and SPB fields shall be set accordingly. However, if the transmitter side is the mobile station and the RESEGMENT bit is not set, the mobile station shall use an MCS within the same family as the initial MCS without splitting the payload (refer to sub-clause 8.1.1, tables 8.1.1.2, 8.1.1.4 and 8.1.1.6) for retransmission.

In case an RLC data block originally transmitted using MCS-8 is retransmitted using two MCS-3 RLC/MAC blocks, the CPS and SPB fields of the first MCS-3 RLC/MAC block shall indicate MCS-3 with (6 octets) padding, whereas the CPS field of the second MCS-3 RLC/MAC block should indicate MCS-3 without padding. In case an RLC data block originally transmitted using DAS-6, DAS-9, DAS-11, DBS-11 or UBS-11 is retransmitted using two MCS-3 RLC/MAC blocks, the CPS and SPB fields of the first MCS-3 RLC/MAC block shall indicate MCS-3 with (6 octets) padding, whereas the CPS field of the second MCS-3 RLC/MAC block shall indicate MCS-3 without padding In case an RLC data block originally transmitted using UAS-8 or UAS-11 is retransmitted using two MCS-3 RLC/MAC blocks, the CPS and SPB fields of the first MCS-3 RLC/MAC block shall indicate MCS-3 with (10 octets) padding, whereas the CPS field of the second MCS-3 RLC/MAC block shall indicate MCS-3 without padding. In case an RLC data block originally transmitted using DAS-7, DAS-10 or DAS-12 is retransmitted using three MCS-2 RLC/MAC blocks, the CPS field of the first MCS-2 RLC/MAC block shall indicate MCS-2 with (2 octets) padding whereas the CPS field of the remaining two MCS-2 RLC/MAC blocks shall indicate MCS-2 without padding.

The selection of MCS is controlled by the network.

The RLC data blocks shall first be sent with one of the initial code rates (i.e. the rate 1/3 encoded data is punctured with the Puncturing Scheme (PS) 1 of the selected MCS). If the RLC data block needs to be retransmitted, additional coded bits (i.e. the output of the rate 1/3 encoded data which is punctured with PS 2 of the prevailing MCS) shall be sent. If all the codewords (different punctured versions of the encoded data block) have been sent, the procedure shall start over and the first codeword (which is punctured with PS 1) shall be sent followed by PS 2 etc. RLC data blocks which are retransmitted using a new MCS shall at the first transmission after the MCS switch be sent with the puncturing scheme indicated in table 9.3.2.1.1.

Table 9.3.2.1.1: RLC data blocks re-transmitted in new MCS

MCS switched from	MCS switched to	PS of last transmission before MCS switch	PS of first transmission after MCS switch
MCS-9	MCS-6	PS 1 or PS 3	PS 1
MCS-9	MCS-6	PS 2	PS 2
MCS-6	MCS-9	PS 1	PS 3
MCS-6	MCS-9	PS 2	PS 2
MCS-7	MCS-5	any	PS 1
MCS-5	MCS-7	any	PS 2
all other combinations		any	PS 1

This procedure allows the receiver to operate either in type I or type II hybrid ARQ mode. In the type I ARQ mode, decoding of an RLC data block is solely based on the prevailing transmission (i.e. erroneous blocks are not stored). In the type II ARQ case, erroneous blocks are stored by the receiver and a joint decoding with new transmissions is done. If the memory for IR operation run out in the mobile station, the mobile station shall indicate this by setting the MS OUT OF MEMORY bit in the EGPRS PACKET DOWNLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK TYPE 2, EGPRS PACKET DOWNLINK ACK/NACK TYPE 3, EGPRS PACKET DOWNLINK ACK/NACK DLMC or MBMS DOWNLINK ACK/NACK message (see note). For uplink TBFs, the network may implicitly set the type I mode by ordering the mobile station to use a specific MCS and setting the RESEGMENT bit or type II mode by ordering the mobile station to use a specific MCS and not setting the RESEGMENT bit.

Type II hybrid ARQ is mandatory in EGPRS MS receivers and the associated performance requirements are specified in 3GPP TS 45.005. Furthermore, it is mandatory for an EGPRS MS receiver to be able to perform joint decoding among blocks with different MCSs if the combination of MCSs is one of the following:

– MCS-5 and MCS-7;

– MCS-6 and MCS-9.

Additionally if the mobile station supports EGPRS2-A in the downlink, it is mandatory for the mobile station to be able to perform joint decoding among blocks with different MCSs if the combination of MCSs is one of the following:

– DAS-5 and DAS-8;

– DAS-6, DAS-9 and DAS-11;

– DAS-7, DAS-10 and DAS-12;

and if the mobile station supports EGPRS2-B in the downlink, it is mandatory for the mobile station to be able to perform joint decoding among blocks with different MCSs if the combination of MCSs is one of the following:

– DBS-5, DBS-7, DBS-9, DAS-5 and DAS-8;

– DBS-6, DBS-8, DBS-10 and DBS-12;

– DBS-11, DAS-6, DAS-9 and DAS-11.

NOTE: The MCS selection may take the IR capability of the receiver into account, for example by using a less robust MCS for a given channel quality.

9.3.2.1a Additional functionality in acknowledged EC TBF Mode

In EC TBF mode, the transfer of RLC Data Blocks in the acknowledged RLC/MAC mode may be controlled by a selective type I ARQ mechanism, or by type II hybrid ARQ mechanism, coupled with the numbering of the RLC Data Blocks within one Temporary Block Flow.

A limited number of puncturing schemes is supported in EC TBF mode compared to EGPRS TBF mode. Only one puncturing scheme (PS 1) is used for MCS-1 and MCS-2 and only two puncturing schemes (PS 1 and PS 2) are used for MCS-3 and MCS-4.

For blocks initially transmitted with MCS-8 which are retransmitted using MCS-6 or MCS-3, padding with all zeroes of the first six octets shall be applied. In these cases, the CPS and SPB fields shall be set accordingly. However, if the transmitter side is the mobile station and the RESEGMENT bit is not set, the mobile station shall use an MCS within the same family as the initial MCS without splitting the payload (refer to sub-clause 8.1.1 and table 8.1.1.2) for retransmission.

The selection of MCS is controlled by the network. Only MCS-1 shall be used when the assigned Coverage Class > CC1.

The RLC data blocks shall first be sent with one of the initial code rates (i.e. the rate 1/3 encoded data is punctured with the Puncturing Scheme (PS) 1 of the selected MCS). If the RLC data block was sent with an MCS of MCS-3 or higher and needs to be retransmitted, additional coded bits (i.e. the output of the rate 1/3 encoded data which is punctured with PS 2 of the prevailing MCS) shall be sent. If all the codewords (different punctured versions of the encoded data block) have been sent, the procedure shall start over and the first codeword (which is punctured with PS 1) shall be sent followed by PS 2 etc.

If the RLC data block was sent with MCS-1 or MCS-2 and needs to be retransmitted, the retransmissions shall be performed with the same puncturing scheme as the initial transmission (PS 1).

RLC data blocks which are retransmitted using a new MCS shall at the first transmission after the MCS switch be sent with the puncturing scheme indicated in table 9.3.2.1a.1.

Table 9.3.2.1a.1: RLC data blocks re-transmitted in new MCS

MCS switched from	MCS switched to	PS of last transmission before MCS switch	PS of first transmission after MCS switch
MCS-9	MCS-6	PS 1 or PS 3	PS 1
MCS-9	MCS-6	PS 2	PS 2
MCS-6	MCS-9	PS 1	PS 3
MCS-6	MCS-9	PS 2	PS 2
MCS-7	MCS-5	any	PS 1
MCS-5	MCS-7	any	PS 2
all other combinations		any	PS 1

This procedure allows the receiver to operate either in type I or type II hybrid ARQ mode. In the type I ARQ mode, decoding of an RLC data block is solely based on the prevailing transmission (i.e. erroneous blocks are not stored). In the type II ARQ case, erroneous blocks are stored by the receiver and a joint decoding with new transmissions is done. If the memory for IR operation runs out in the mobile station, the mobile station shall indicate this by setting the MS OUT OF MEMORY bit in the EC PACKET DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK HIGHER CC (see note). For uplink TBFs, the network may implicitly set the type I mode by ordering the mobile station to use a specific MCS and setting the RESEGMENT bit or type II mode by ordering the mobile station to use a specific MCS and not setting the RESEGMENT bit.

Type II hybrid ARQ is mandatory for EC-GSM-IoT capable MS receivers and the associated performance requirements are specified in 3GPP TS 45.005 [30]. Furthermore, it is mandatory for an EC-GSM-IoT capable MS receiver that supports 8-PSK modulation to be able to perform joint decoding among blocks with different MCSs if the combination of MCSs is one of the following:

– MCS-5 and MCS-7;

– MCS-6 and MCS-9.

NOTE: The MCS selection may take the IR capability of the receiver into account, for example by using a less robust MCS for a given channel quality.

9.3.2.2 Establishment of Temporary Block Flow

The establishment of a TBF occurs as described in clause 7 and clause 8. RLC functions related to the ARQ function shall not operate until RLC data block transfer has been initiated.

If the last uplink TBF ended with an incompletely transmitted upper layer PDU or any unacknowledged upper layer PDUs, the mobile station shall begin transmission on the new TBF with the oldest unacknowledged upper layer PDU.

9.3.2.3 Operation of uplink Temporary Block Flow

The mobile station shall transmit an RLC/MAC block in each assigned uplink data block. RLC/MAC control blocks have preference to RLC data blocks, i.e. temporarily replacing the PDTCH with PACCH, except for an uplink EC TBF, for which EC-PACCH blocks shall not replace EC-PDTCH blocks.

The network shall send (EC) PACKET UPLINK ACK/NACK messages when needed.

The mobile station shall indicate a transmit window stall condition when V(S) = V(A) + WS. Upon detecting a transmit window stall condition, the mobile station shall set the Stall indicator (SI) bit in all subsequent uplink RLC data blocks for this TBF, or if EMST is used, for the associated RLC entity, until the stall condition ceases to exist. An exception is the case of a mobile station using an EC TBF where the Stall indicator (SI) is not supported.

Upon detecting the stall condition the mobile station shall also start timer T3182 for the TBF, or if EMST is used, for the associated RLC entity. Timer T3182 shall be stopped upon reception of a PACKET UPLINK ACK/NACK message that makes V(S) < V(A) + WS. If timer T3182 expires, the mobile station shall decrement counter N3102 by PAN_DEC, and proceed as follows:

– If there are no other ongoing uplink TBFs and one or no ongoing downlink TBFs perform an abnormal release with access retry (see sub-clause 8.7.2) (A/Gb mode).

– If there are one or more other ongoing uplink TBFs or multiple ongoing downlink TBFs, perform a multiple TBF abnormal release with access retry (see sub-clause 8.7.4).

Whenever the mobile station receives a PACKET UPLINK ACK/NACK message that allows the advancement of V(S) or V(A), the mobile station shall increment N3102 by PAN_INC, however N3102 shall never exceed the value PAN_MAX. Upon cell reselection the mobile station shall set counter N3102 to the value PAN_MAX. When N3102 £ 0 is reached, the mobile station shall perform an abnormal release with cell re-selection (see sub-clause 9.4.2). If PAN_DEC or PAN_INC is set to the value 0, counter N3102 shall be disabled.

Timer T3182 and counter N3102 shall not be used in EC TBF mode. A mobile station in EC TBF mode shall, if it in a fixed uplink allocation is allocated additional resources to what is needed to transmit each RLC data block within the transmit window, perform pre-emptive retransmission in those additional resources (see sub-clause 9.1.3.4).

A mobile station operating with an exclusive allocation shall start or restart timer T3184 upon reception of a PACKET UPLINK ACK/NACK message. If timer T3184 expires, the mobile station shall perform an abnormal release with access retry (see sub-clause 9.4.2).

If a mobile station with an uplink EC TBF, while monitoring the downlink EC-PACCH, receives an RLC/MAC block containing RLC data blocks (thus not intended for the mobile station), it may use the Coverage Class (CC) field in the RLC data block header, if present, to determine that it may avoid listening to the EC-PACCH while repetitions of the ongoing transmission (for a higher Coverage Class to another mobile station) are being transmitted. If the mobile station receives an RLC/MAC block, which is an RLC/MAC control message on the EC-PACCH, which is not addressed to the mobile station, it may use the USED_DL_COVERAGE_CLASS information in the message to determine that it may avoid listening to the EC-PACCH while repetitions of the ongoing transmission (for a higher Coverage Class to another mobile station) are being transmitted.

If a mobile station with an uplink EC TBF receives an RLC/MAC control message addressed to it on the EC-PACCH, it shall accept the message even if the USED_DL_COVERAGE_CLASS information in the message indicates a different downlink Coverage Class than what is assigned to the mobile station.

9.3.2.4 Release of uplink Temporary Block Flow

9.3.2.4.1 General

In the non-extended uplink TBF mode, the mobile station initiates the release of the uplink TBF by beginning the countdown process (see sub-clause 9.3.1).

In the extended uplink TBF mode, the network determines when to release the uplink TBF. The release of an uplink TBF in the extended uplink TBF mode is performed by the procedure defined in sub-clause 9.5.

9.3.2.4.2 Non-extended uplink TBF mode

When the mobile station has sent the RLC data block with CV = 0 and there are no elements in the V(B) array set to the value Nacked, it shall start timer T3182 for this TBF. The mobile station shall continue to send RLC data blocks on each assigned uplink data block, according to the algorithm defined in sub-clause 9.1.3.

If the network has received all RLC data blocks when it detects the end of the TBF (i.e. when CV=0 and V(Q) = V(R)), it shall send the PACKET UPLINK ACK/NACK message with the Final Ack Indicator bit set to ‘1’, include a valid RRBP field in the RLC/MAC control block header and clear counter N3103 for the TBF. The network may use the TBF Est field in the PACKET UPLINK ACK/NACK message to allow the mobile station to request the establishment of a new uplink TBF if there are no additional TBFs ongoing for that mobile station.

If the network has not received all of the RLC data blocks when it detects the end of the TBF, it shall send a PACKET UPLINK ACK/NACK message to the mobile station and if necessary allocate sufficient uplink resources for the mobile station to retransmit the required RLC data blocks.

Upon reception of a PACKET UPLINK ACK/NACK message for this TBF the mobile station shall stop timer T3182 for the TBF.

If the PACKET UPLINK ACK/NACK message has the Final Ack Indicator bit set to ‘1’ and the following conditions are fulfilled: TBF Est field is set to ‘1’; the mobile station has new data to transmit; the mobile station has no other ongoing downlink TBFs, the mobile station shall release the uplink TBF and may request the establishment of a new TBF using one of the following procedures:

– If Control Ack Type parameter in System Information indicates acknowledgement is access burst, the mobile station shall transmit the PACKET CONTROL ACKNOWLEDGEMENT message with the Ctrl Ack bits set to ’00’. The mobile station shall start timer T3168 for the TBF request and continue to monitor the PDCH used for transmitting the PACKET CONTROL ACKNOWLEDGEMENT message. The mobile station shall stop timer T3168 for the TBF upon reception of the PACKET UPLINK ASSIGNMENT message including Single Block Allocation structure assigning resources for the TBF or the PACKET ACCESS REJECT message rejecting the TBF request. The mobile station shall use the same procedures as are used for TBF establishment using two phase access described in sub-clause 7.1.3 starting from the point where the mobile station receives the PACKET UPLINK ASSIGNMENT message including Single Block Allocation structure or the PACKET ACCESS REJECT message.

– If Control Ack Type parameter in System Information indicates acknowledgement is RLC/MAC control block, the mobile station shall transmit the PACKET RESOURCE REQUEST message and start timer T3168 for the TBF request. The mobile station shall use the same procedures as are used for TBF establishment using two phase access described in sub-clause 7.1.3 starting from the point where the mobile station transmits the PACKET RESOURCE REQUEST message.

If the PACKET UPLINK ACK/NACK message has the Final Ack Indicator bit set to ‘1’ and the mobile station does not initiate the establishment of a new uplink TBF according to one of the procedures described above, the mobile station shall transmit the PACKET CONTROL ACKNOWLEDGEMENT message and release the TBF. If there is no other ongoing TBFs, the mobile station in packet transfer mode or MAC-Shared state shall return to packet idle mode or MAC-Idle state; the mobile station in dual transfer mode or MAC-DTM state shall return to dedicated mode or MAC-Dedicated state. The DRX mode procedures shall be applied as specified in sub-clause 5.5.1.5. If there are one or more ongoing TBFs a mobile station shall remain in its current mode/state and can request additional uplink TBFs as follows:

– It may send a PACKET RESOURCE REQUEST message using the PACCH if there is at least one ongoing uplink TBF as described in sub-clause 8.1.1.1.2.

– It may include a Channel Request Description or the Extended Channel Request Description information element in the (EGPRS) PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message or a Channel Request Description information element in the EGPRS PACKET DOWNLINK ACK/NACK DLMC message if there are no ongoing uplink TBFs and at least one ongoing downlink TBF as described in sub-clause 8.1.2.5.

If the PACKET UPLINK ACK/NACK message requests retransmission of RLC data blocks, the mobile station shall if necessary wait for allocation of uplink resources for this TBF and then retransmit the RLC data blocks requested. The mobile station shall then start timer T3182 for the TBF and wait for a PACKET UPLINK ACK/NACK message as above.

If timer T3182 expires for the TBF the mobile station shall perform an abnormal release with access retry (see sub-clause 8.7.2) (A/Gb mode).

When the network receives the PACKET CONTROL ACKNOWLEDGEMENT message or the PACKET RESOURCE REQUEST message in the radio block indicated by the RRBP field, it may reuse the TFI and USF resources.

If the network receives the PACKET CONTROL ACKNOWLEDGEMENT message with Ctrl Ack bits set to ’00’ or the PACKET RESOURCE REQUEST message in the radio block indicated by the RRBP field and the network has set the TBF Est field to ‘1’ in the PACKET UPLINK ACK/NACK message, the network shall follow one of the following procedures:

– In case the mobile station requested the establishment of new TBF with the PACKET CONTROL ACKNOWLEDGEMENT message, the network shall respond to the mobile station with the PACKET UPLINK ASSIGNMENT message including Single Block Allocation structure or the PACKET ACCESS REJECT message on the same PDCH as the mobile station has sent the PACKET CONTROL ACKNOWLEDGEMENT message. TLLI (in A/Gb mode) or the G-RNTI (in Iu mode) shall be used to identify the mobile station. The network shall use the same procedures as are used for TBF establishment using two phase access described in sub-clause 7.1.3 (A/Gb mode) starting from the point where the network transmits the PACKET UPLINK ASSIGNMENT message including Single Block Allocation structure or the PACKET ACCESS REJECT message.

– In case the mobile station requested the establishment of new TBF with the PACKET RESOURCE REQUEST message, the network shall use the same procedures as are used for TBF establishment using two phase access described in sub-clause 7.1.3 (A/Gb mode) starting from the point where the network has received the PACKET RESOURCE REQUEST message. TLLI (in A/Gb mode) or the G-RNTI (in Iu mode) shall be used to identify the mobile station.

If the network does not receive the PACKET CONTROL ACKNOWLEDGEMENT message or the PACKET RESOURCE REQUEST message in the radio block indicated by the RRBP field, it shall increment counter N3103 for the TBF and retransmit the PACKET UPLINK ACK/NACK message. If counter N3103 exceeds its limit, the network shall start timer T3169 for the TBF. When timer T3169 expires for the TBF the network may reuse the TFI and USF resources.

9.3.2.4.3 Release of uplink EC TBF

When the network has received all RLC data blocks for a TBF (i.e. all RLC data blocks that the mobile station has indicated as part of the TBF have been received), it shall send the EC PACKET UPLINK ACK/NACK message with the Final Ack Indicator bit set to ‘1’. The network may include a valid RRBP field in the RLC/MAC control block header in order to poll the mobile station for an EC PACKET CONTROL ACKNOWLEDGEMENT or EC PACKET DOWNLINK ACK/NACK HIGHER CC message. The network shall then clear counter N3103 for the TBF at transmission of the EC PACKET UPLINK ACK/NACK message.

When the mobile station receives the EC PACKET UPLINK ACK/NACK message with the Final Ack Indicator bit set to ‘1’ and including a valid RRBP field in the RLC/MAC control block header, it shall transmit an EC PACKET CONTROL ACKNOWLEDGEMENT or EC PACKET DOWNLINK ACK/NACK HIGHER CC message in the uplink resources indicated by the RRBP field. The EC PACKET CONTROL ACKNOWLEDGEMENT or EC PACKET DOWNLINK ACK/NACK HIGHER CC message shall be sent according to the last assigned UL Coverage Class.

The network may, in the EC PACKET UPLINK ACK/NACK message with the Final Ack Indicator bit set to ‘1’, indicate that the mobile station shall continue monitoring the EC-PACCH for some time, for possible reception of a downlink RLC/MAC control message, before returning to packet idle mode, see sub-clause 11.2.57. The network shall then start timer T3237 at transmission of the EC PACKET UPLINK ACK/NACK message. If the mobile station is not indicated to continue monitoring the EC-PACCH, it shall return directly to packet idle mode after reception of the message and, if so indicated by the network, transmission of the EC PACKET CONTROL ACKNOWLEDGEMENT or EC PACKET DOWNLINK ACK/NACK HIGHER CC message.

If the mobile station, in the EC PACKET UPLINK ACK/NACK message with the Final Ack Indicator bit set to ‘1’, has been indicated to continue monitoring the EC-PACCH, it shall start timer T3238. The mobile station shall then monitor the EC-PACCH, according to its assigned downlink Coverage Class of the TBF, after an initial waiting time as indicated in the EC PACKET UPLINK ACK/NACK message. The mobile station shall then monitor the EC-PACCH, using a monitoring pattern as indicated in the EC PACKET UPLINK ACK/NACK message, until timer T3238 expires or until a downlink RLC/MAC control message triggering the release of the TBF is received. When timer T3238 expires, the mobile station shall leave the TBF and return to packet idle mode.

If the mobile station receives an EC PACKET DOWNLINK ASSIGNMENT message addressing the mobile station while listening to the EC-PACCH, it shall stop timer T3238, release the uplink TBF and act on the assigned resources.

In case the mobile station receives an EC PACKET DOWNLINK ASSIGNMENT message addressing the mobile station after it has transmitted the last RLC data block, with CV=0, but prior to reception of the EC PACKET UPLINK ACK/NACK message with the Final Ack Indicator bit set to ‘1’, it shall consider all the transmitted RLC data blocks as acknowledged, release the uplink TBF and act on the assigned resources.

After returning to packet idle mode, the mobile station shall, as long as the Ready timer is still running, listen to its paging group on the EC-CCCH using the lowest eDRX cycle, see 3GPP TS 45.002 [13].

When the EC PACKET CONTROL ACKNOWLEDGEMENT or EC PACKET DOWNLINK ACK/NACK HIGHER CC message is received in the radio block indicated by the RRBP field, the network may release the TBF and reuse the TFI resource directly unless the mobile station has been indicated to continue monitoring the EC-PACCH in the EC PACKET UPLINK ACK/NACK message, in which case the network may release the TBF and reuse the TFI resource when timer T3237 expires.

If the network does not receive the EC PACKET CONTROL ACKNOWLEDGEMENT or EC PACKET DOWNLINK ACK/NACK HIGHER CC message in the resources indicated by the RRBP field, it shall increment counter N3103 for the TBF and retransmit the EC PACKET UPLINK ACK/NACK message in the next available DL EC-PACCH occasion for the TBF, unless N3103 has exceeded its limit. If the EC PACKET UPLINK ACK/NACK message contains an indication that the mobile station shall continue monitoring the EC-PACCH for some time before returning to packet idle mode, the network shall restart timer T3237 at transmission of the message.

When timer T3229 expires for the TBF the network may release the TBF and reuse the TFI resource, unless timer T3237 is still running.

9.3.2.5 Operation of downlink Temporary Block Flow

The mobile station receives RLC/MAC blocks on the assigned downlink PDCHs. On each assigned PDCH, the mobile station shall in the RLC header identify the TFI and decode the RLC data blocks intended for the mobile station.

A mobile station with a downlink EC TBF receives RLC/MAC blocks on the downlink EC-PDTCH/EC-PACCH that is part of the TBF. Each RLC/MAC block in the TBF may then be transmitted with a fixed number of blind physical layer transmissions, depending on the Coverage Class that the TBF has been assigned for, see 3GPP TS 45.002 [13]. An RLC/MAC block is received on the EC-PDTCH/EC-PACCH, which thus is mapped to one or several PDCHs, depending on the Coverage Class. A downlink EC TBF, assigned for Coverage Class 1, may consist of more than one EC-PDTCH/EC-PACCH, in which case the mobile station shall receive RLC/MAC blocks on more than one EC-PDTCH/EC-PACCH.

The mobile station shall identify the TFI in the RLC header of the RLC/MAC blocks containing RLC data blocks that are received on the EC-PDTCH, and decode the RLC data blocks intended for the mobile station. If the RLC/MAC block, containing RLC data blocks, is not intended for the mobile station, it may use the Coverage Class (CC) field in the RLC data block header, if present, to determine that it may avoid listening to the EC-PDTCH/EC-PACCH while repetitions of the ongoing transmission (for a higher Coverage Class to another mobile station) are being transmitted.

If the mobile station receives an RLC/MAC block, containing RLC data blocks, which is intended for the mobile station, it shall accept the RLC/MAC block even if the Coverage Class (CC) field in the RLC data block header indicates a different downlink Coverage Class than what is assigned to the mobile station.

If the RLC/MAC block is an RLC/MAC control message received on the EC-PACCH, which is not addressed to the mobile station, it may use the USED_DL_COVERAGE_CLASS information in the message to determine that it may avoid listening to the EC-PDTCH/EC-PACCH while repetitions of the ongoing transmission (for a higher Coverage Class to another mobile station) are being transmitted.

If the mobile station receives an RLC/MAC control message addressed to it on the EC-PACCH, it shall accept the message even if the USED_DL_COVERAGE_CLASS information in the message indicates a different downlink Coverage Class than what is assigned to the mobile station.

The operation during the TBF shall be as defined in sub-clause 9.1.

9.3.2.6 Release of downlink Temporary Block Flow

If EMST is used (see sub-clause 5.10), the network shall release a downlink TBF by releasing all the RLC entities allocated on that TBF. The downlink TBF is successfully released when the last RLC entity is released. The network shall perform the release of an RLC entity operating in RLC acknowledged mode as specified in the present sub-clause. The network shall perform the release of an RLC entity operating in RLC unacknowledged mode as specified in sub-clause 9.3.3.5.

The network initiates the release of a downlink TBF, or if EMST is used, the release of an RLC entity on the downlink TBF by sending an RLC data block with the Final Block Indicator (FBI) set to the value ‘1’ and with a valid RRBP field. The RLC data block sent must have the highest BSN’ (see sub-clause 9.3.1) of the downlink TBF, or if EMST is used, of the RLC entity. The network shall start timer T3191 for the TBF, or if EMST is used, for the RLC entity. While timer T3191 is running for the TBF the network may retransmit the RLC data block with the FBI bit set to the value ‘1’. For each retransmission the timer T3191 is restarted.

In EGPRS TBF mode or EC TBF mode, if the final RLC data block is split for retransmission over two radio blocks (see sub-clause 9.3.2.1 for EGPRS TBF mode and sub-clause 9.3.2.1a for EC TBF mode), the network shall set the FBI to the value ‘1’ in each part of the retransmitted RLC data block.

If the mobile station receives an RLC data block (or, in EGPRS TBF mode or EC TBF mode, a part of a retransmitted RLC data block) with the FBI bit set the value ‘1’ and with a valid RRBP field, the mobile station shall transmit a (EGPRS) PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC or EC PACKET DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK HIGHER CC message in the specified uplink block. The mobile station shall continue to monitor all assigned PDCHs. The mobile station in EC TBF mode shall continue to monitor the assigned EC-PDTCH(s)/EC-PACCH(s).

Whenever the mobile station receives an RLC data block (or, in EGPRS TBF mode or EC TBF mode, a part of a retransmitted RLC data block) with a valid RRBP and the mobile station has received all RLC data blocks of the TBF, the mobile station shall send the (EGPRS) PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC or EC PACKET DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK HIGHER CC message with the Final Ack Indicator bit set to ‘1’ in the reserved uplink radio block specified by the RRBP field, stop the timer T3190 for the TBF. If EMST is used, the mobile station shall stop the timer T3190 only if the (EGPRS) PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC message with the Final Ack Indicator bit set to ‘1’ corresponds to the last remaining RLC entity on the TBF. If the timeout value of timer T3192 (see sub-clause 12.24 or, for EC TBF mode, 3GPP TS 44.018 [11]) is different from 0 ms then the mobile station shall start or restart timer T3192 for the TBF, or if EMST is used, for the RLC entity and continue to monitor all assigned downlink PDCHs. Otherwise, if the timeout value of timer T3192 is 0 ms then the mobile station shall follow the same procedure as if the timer T3192 has expired.

In GPRS TBF mode, if the mobile station receives more than one RLC data block with the FBI set to ‘1’, it shall accept the data from only the first one of these blocks.

If the network receives a (EGPRS) PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC or EC PACKET DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK HIGHER CC message for the TBF, or if EMST is used, for the RLC entity before its timer T3191 expires, and if retransmissions are required, then the network stops timer T3191 for the TBF, or if EMST is used, for the RLC entity and retransmits necessary RLC data blocks according to the ARQ protocol before re-initiating the release of the downlink TBF, or if EMST is used, of the RLC entity. The FBI is set to ‘1’ only if the RLC data block with the highest BSN’ of the TBF, or if EMST is used, of the RLC entity is retransmitted. If no retransmission is required, the network shall stop timer T3191 for the TBF, or if EMST is used, for the RLC entity and start or restart timer T3193 for the TBF, or if EMST is used, of the RLC entity. When T3193 expires the network shall release the TBF, or if EMST is used, the associated RLC entity.

If timer T3191 expires for the TBF, then the network shall release the TBF, or if EMST is used, the associated RLC entity.

If the network has received the (EGPRS) PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC message with the Final Ack Indicator bit set to ‘1’ and has new data to transmit for the mobile station that cannot be transmitted on any ongoing downlink TBF, the network may establish one or more new downlink TBF(s) for the mobile station by sending on PACCH the PACKET DOWNLINK ASSIGNMENT, MULTIPLE TBF DOWNLINK ASSIGNMENT, PACKET TIMESLOT RECONFIGURE or MULTIPLE TBF TIMESLOT RECONFIGURE message with the Control Ack bit set to ‘1’ for each TBF. The network may send these downlink assignment messages using the PACCH of any ongoing TBF for the mobile station. In case the network establishes a new downlink TBF for the mobile station, or if EMST is used, reconfigures the ongoing TBF using the PACCH of a downlink TBF for which T3193 is running, the network shall stop that instance of timer T3193 and release that TBF, or if EMST is used, the associated RLC entity. The abnormal cases are described in sub-clause 8.1.2.4.1.

If the network has received the EC PACKET DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK HIGHER CC message with the Final Ack Indicator bit set to ‘1’ from a mobile station in EC TBF mode and has new data to transmit for the mobile station while the timer T3193 is still running, the network may establish a new downlink TBF for the mobile station by sending on EC-PACCH the EC PACKET DOWNLINK ASSIGNMENT message. The network shall then release the old TBF and stop that instance of timer T3193.

After receiving an EC PACKET DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK HIGHER CC message in TDMA frame N the network shall resume downlink transmissions to the corresponding mobile station on its assigned PDCH(s) according to the assigned downlink coverage class of the mobile station and may start as early downlink TDMA frame N+1 depending on the assigned uplink and downlink coverage classes.

If the mobile station, after sending the PACKET DOWNLINK ACK/NACK message with the Final Ack Indicator bit set to ‘1’ for a given TBF, receives a PACKET DOWNLINK ASSIGNMENT, MULTIPLE TBF DOWNLINK ASSIGNMENT, PACKET TIMESLOT RECONFIGURE or MULTIPLE TBF TIMESLOT RECONFIGURE message with the Control Ack bit set to ‘1’ on the PACCH associated with this TBF while its timer T3192 is running, or if EMST is used, the timer T3192 associated with the RLC entity identified by the TFI included in the message is running, the mobile station shall stop this instance of timer T3192, consider this downlink TBF released, or if EMST is used, consider the associated RLC entity released and act upon the new assignments.

If the mobile station in EC TBF mode, after sending the EC PACKET DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK HIGHER CC message with the Final Ack Indicator bit set to ‘1’, receives an EC PACKET DOWNLINK ASSIGNMENT message on the EC-PACCH associated with this TBF while its timer T3192 is running, the mobile station shall stop this instance of timer T3192, consider this downlink TBF released and act upon the new assignments.

When timer T3192 expires the mobile station shall release the associated downlink TBF, or if EMST is used, the associated RLC entity. If there are no other ongoing TBFs, or if EMST is used, no other ongoing RLC entities, the mobile station in packet transfer mode or MAC-Shared state shall return to packet idle mode or MAC-Idle state; the mobile station in dual transfer mode respectively MAC-DTM state shall return to dedicated mode or MAC-Dedicated state. The DRX mode procedures shall be applied, as specified in sub-clause 5.5.1.5. If there are one or more ongoing TBFs a mobile station shall remain in its current mode/state and can request additional uplink TBFs as follows:

– It may send a PACKET RESOURCE REQUEST message using the PACCH if there is at least one ongoing uplink TBF as described in sub-clause 8.1.1.1.2.

– It may include a Channel Request Description or the Extended Channel Request Description information element in the (EGPRS) PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message if there are no ongoing uplink TBFs and at least one ongoing downlink TBF as described in sub-clause 8.1.2.5.

The mobile station in EC TBF mode may include an EC Channel Request Description in the EC PACKET DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK HIGHER CC message in order to request an uplink TBF. The network may then establish an uplink EC TBF for the mobile station by sending an EC PACKET UPLINK ASSIGNMENT message, in which case the downlink EC TBF is released. When transmitting the EC PACKET DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK HIGHER CC message with the EC Channel Request Description, the mobile station shall start timer T3168 and listen to the EC-PACCH of the downlink TBF as described in sub-clause 8.1.2.5. When the mobile station receives an EC PACKET UPLINK ASSIGNMENT allocating resources for the request in the EC PACKET DOWNLINK ACK/NACK or EC PACKET DOWNLINK ACK/NACK HIGHER CC message, it shall stop timers T3168 and T3192, if running, release the downlink TBF and act on the new assignment. The mobile station shall also stop timer T3168 at reception of an EC PACKET ACCESS REJECT message, in which case the mobile station shall continue monitoring the assigned EC-PDTCH/EC-PACCH resources of the downlink TBF.

9.3.3 Unacknowledged mode operation

9.3.3.0 General

The transfer of RLC data blocks in the RLC unacknowledged mode does not include any retransmissions, except during the release of a TBF where the last transmitted block may be retransmitted (see sub-clauses 9.3.3.3 and 9.3.3.5). In EGPRS TBF mode, retransmission with segmentation method shall not be used. The block sequence number (BSN) in the RLC data block header is used to number the RLC data blocks for reassembly.

The receiving RLC endpoint shall expect all RLC data blocks received in the same radio block period were sent in increasing order of BSN (apart from the last transmitted block of a TBF). As an exception, in a downlink dual carrier configuration or a DLMC configuration, the mobile station shall never expect RLC data blocks received in the same radio block period to have been sent in any specific order of BSN. In this case the mobile station shall re-order the received RLC data blocks before detecting any missing RLC data blocks.

The receiving side sends Packet Ack/Nack messages in order to convey the necessary other control signalling (e.g. monitoring of channel quality for downlink transfer or timing advance correction for uplink transfers).

9.3.3.1 Establishment of Temporary Block Flow

If the last uplink TBF ended with an incompletely transmitted upper layer PDU, the mobile station shall begin transmission on the new TBF with the last incompletely transmitted upper layer PDU.

9.3.3.2 Operation of uplink Temporary Block Flow

The network shall send PACKET UPLINK ACK/NACK messages when needed.

The mobile station shall set the Stall indicator (SI) bit to ‘0’ in all RLC data blocks of the TBF.

If the mobile station transmits the number of RLC data blocks corresponding to the RLC window size (WS),without receiving a Packet Ack/Nack message the mobile station shall start timer T3182 for the TBF. Timer T3182 shall be stopped upon reception of a PACKET UPLINK ACK/NACK message for this TBF. If timer T3182 expires, the mobile station shall decrement counter N3102 by PAN_DEC, and perform an abnormal release with access retry (see sub-clause 8.7.2 (A/Gb mode).

Whenever the mobile station receives a PACKET UPLINK ACK/NACK message, the mobile station shall increment N3102 by PAN_INC, however N3102 shall never exceed the value PAN_MAX. Upon cell reselection the mobile station shall set counter N3102 to the value PAN_MAX. When N3102 £ 0 is reached, the mobile station shall perform an abnormal release with cell re-selection (see sub-clause 9.4.2). If PAN_DEC or PAN_INC is set to the value 0, counter N3102 shall be disabled.

9.3.3.3 Release of uplink Temporary Block Flow

9.3.3.3.1 General

In the non-extended uplink TBF mode, the mobile station initiates the release of the uplink TBF by beginning the countdown process (see sub-clause 9.3.1).

9.3.3.3.2 Non-extended uplink TBF mode

The mobile station indicates the end of the TBF by sending the RLC data block with CV = 0. The mobile station shall start timer T3182 for the TBF.

When the network detects the end of the TBF (i.e. when CV=0) it shall send a PACKET UPLINK ACK/NACK message with the Final Ack Indicator bit set to ‘1’, include a valid RRBP field in the RLC/MAC control block header and clear counter N3103 for the TBF. The network may use the TBF Est field in the PACKET UPLINK ACK/NACK message to allow the mobile station to request the establishment of a new uplink TBF if there are no additional TBFs ongoing for that mobile station.

In case the network receives multiple blocks with CV=0, only the first needs to be acknowledged with PACKET UPLINK ACK/NACK message.

Upon reception of a PACKET UPLINK ACK/NACK message for this TBF the mobile station shall stop timer T3182 for the TBF.

If the PACKET UPLINK ACK/NACK message has the Final Ack Indicator bit set to ‘1’ and the mobile station does not initiate the establishment of a new uplink TBF according to one of the procedures described below, the mobile station shall transmit the PACKET CONTROL ACKNOWLEDGEMENT message and release the TBF. If there are no other ongoing TBFs, the mobile station in packet transfer mode or MAC-Shared state shall enter packet idle mode or MAC-Idle state; the mobile station in dual transfer mode MAC-DTM state shall return to dedicated mode or MAC-Dedicated state. The DRX mode procedures shall be applied, as specified in sub-clause 5.5.1.5. If there are one or more ongoing TBFs a mobile station shall remain in its current mode/state and can request additional uplink TBFs as follows:

– It may send a PACKET RESOURCE REQUEST message using the PACCH if there is at least one ongoing uplink TBF as described in sub-clause 8.1.1.1.2.

If the PACKET UPLINK ACK/NACK message has the Final Ack Indicator bit set to ‘1’ and the following conditions are fulfilled: TBF Est field is set to ‘1’; the mobile station has new data to transmit; the mobile station has no other ongoing TBFs, the mobile station shall release the uplink TBF and may request the establishment of a new TBF using one of the following procedures:

– If Control Ack Type parameter in System Information indicates acknowledgement is access burst, the mobile station shall transmit the PACKET CONTROL ACKNOWLEDGEMENT message with the Ctrl Ack bits set to ’00’. The mobile station shall start timer T3168 for the TBF request and continue to monitor the PDCH used for transmitting the PACKET CONTROL ACKNOWLEDGEMENT message. The mobile station shall stop timer T3168 for the TBF upon reception of the PACKET UPLINK ASSIGNMENT message including Single Block Allocation structure assigning resources for the TBF or the PACKET ACCESS REJECT message rejecting the TBF request. The mobile station shall use the same procedures as are used for TBF establishment using two phase access described in sub-clause 7.1.3 (A/Gb mode) starting from the point where the mobile station receives the PACKET UPLINK ASSIGNMENT message including Single Block Allocation structure or the PACKET ACCESS REJECT message.

– If Control Ack Type parameter in System Information indicates acknowledgement is RLC/MAC control block, the mobile station shall transmit the PACKET RESOURCE REQUEST message and start timer T3168 for the TBF request. The mobile station shall use the same procedures as are used for TBF establishment using two phase access described in sub-clause 7.1.3 (A/Gb mode) starting from the point where the mobile station transmits the PACKET RESOURCE REQUEST message.

If the PACKET UPLINK ACK/NACK message does not have the Final Ack Indicator bit set to ‘1’, the mobile station shall repeat sending the last block with CV=0, until a PACKET UPLINK ACK/NACK message with Final Ack Indicator bit set to ‘1’ is received for this TBF. Upon each retransmission of the last block with CV=0, the mobile station shall restart timer T3182 for the TBF. The block with CV=0 shall not be retransmitted more than four times. If the medium access mode is dynamic allocation, the repetitions are transmitted when the mobile station is scheduled USFs. If timer T3182 expires for the TBF the mobile station shall release the TBF as if a PACKET UPLINK ACK/NACK message was received.

When the network receives the PACKET CONTROL ACKNOWLEDGEMENT message or the PACKET RESOURCE REQUEST message in the radio block indicated by the RRBP field, it may reuse the TFI and USF resources.

– In case the mobile station requested the establishment of new TBF with the PACKET CONTROL ACKNOWLEDGEMENT message, the network shall respond to the mobile station with the PACKET UPLINK ASSIGNMENT message including Single Block Allocation structure or the PACKET ACCESS REJECT message on the same PDCH as the mobile station has sent the PACKET CONTROL ACKNOWLEDGEMENT message. TLLI (in A/Gb mode) or G-RNTI (in Iu mode) shall be used to identify the mobile station. The network shall use the same procedures as are used for TBF establishment using two phase access described in sub-clause 7.1.3 (A/Gb mode) starting from the point where the network transmits the PACKET UPLINK ASSIGNMENT message including Single Block Allocation structure or the PACKET ACCESS REJECT message.

– In case the mobile station requested the establishment of new TBF with the PACKET RESOURCE REQUEST message, the network shall use the same procedures as are used for TBF establishment using two phase access described in sub-clause 7.1.3 (A/Gb mode) starting from the point where the network has received the PACKET RESOURCE REQUEST message. TLLI (in A/Gb mode) or G-RNTI (in Iu mode) shall be used to identify the mobile station.

If the network does not receive the PACKET CONTROL ACKNOWLEDGEMENT message or the PACKET RESOURCE REQUEST message for the TBF in the radio block indicated by the RRBP field, it shall increment counter N3103 and retransmit the PACKET UPLINK ACK/NACK message for the TBF. If counter N3103 exceeds its limit, the network shall start timer T3169 for the TBF. When timer T3169 expires for the TBF the network may reuse the TFI and USF resources.

9.3.3.4 Operation of downlink Temporary Block Flow

9.3.3.5 Release of downlink Temporary Block Flow

If EMST is used (see sub-clause 5.10), the network shall release a downlink TBF by releasing all the RLC entities allocated on that TBF. The downlink TBF is successfully released when the last RLC entity is released. The network shall perform the release of an RLC entity operating in RLC unacknowledged mode as specified in the present sub-clause. The network shall perform the release of an RLC entity operating in RLC acknowledged mode as specified in sub-clause 9.3.2.6.

The network initiates the release of a downlink TBF, or if EMST is used, the release of an RLC entity on a downlink TBF by sending an RLC data block with the Final Block Indicator (FBI) set to the value ‘1’ and with a valid RRBP field. The RLC data block sent must have the highest BSN’ (see sub-clause 9.3.1) of the downlink TBF, or if EMST is used, of the RLC entity. The network shall start timer T3191 for the TBF, or if EMST is used, for the RLC entity. The network may retransmit the last block with FBI set to the value ‘1’ and with a valid RRBP field. For each retransmission for the TBF, or if EMST is used, for each retransmission for the RLC entity, the timer T3191 is restarted.

For each RLC data block with the FBI bit set to ‘1’ and with a valid RRBP field, the mobile station shall transmit the PACKET CONTROL ACKNOWLEDGEMENT message in the uplink block specified by the RRBP field. The mobile station shall continue to read the assigned downlink PDCHs until the block period pointed to by the RRBP. If the mobile station receives more than one RLC data block with the FBI bit set to ‘1’ and with valid RRBP fields that point the same uplink block period, the mobile station shall transmit the PACKET CONTROL ACKNOWLEDGEMENT message only once. The mobile station shall then stop timer T3190 for the TBF. If EMST is used, the mobile station shall stop the timer T3190 only if the (EGPRS) PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC message with the Final Ack Indicator bit set to ‘1’ corresponds to the last remaining RLC entity on the TBF. If the timeout value of timer T3192 (see sub-clause 12.24) is different from 0 ms then the mobile station shall start timer T3192 for the TBF, or if EMST is used, for the RLC entity and continue to monitor all assigned downlink PDCHs. Otherwise, if the timeout value of timer T3192 is 0 ms then the mobile station shall follow the procedure as if the timer T3192 has expired.

If the mobile station then receives a subsequent RLC data block with a valid RRBP and the FBI bit set to ‘1’, the mobile station shall retransmit the PACKET CONTROL ACKNOWLEDGEMENT message and restart timer T3192 for the TBF, or if EMST is used, for the associated RLC entity.

In GPRS TBF mode, if the mobile station receives more than one RLC data block with the FBI set to ‘1’ for the same RLC instance, it shall accept the data from only the first one of these blocks.

If the network receives the PACKET CONTROL ACKNOWLEDGEMENT message for the TBF, or if EMST is used, for the RLC entity before timer T3191 expires, the network shall stop timer T3191 for the TBF, or if EMST is used, for the associated RLC entity and start or restart timer T3193 for the TBF, or if EMST is used, for the RLC entity. When T3193 expires the network shall release the TBF, or if EMST is used, the associated RLC entity.

If timer T3191 expires, the network shall release the associated TBF, or if EMST is used, the associated RLC entity.

If the network has received the PACKET CONTROL ACKNOWLEDGEMENT message and has new data to transmit for the mobile station, the network may establish one or more new downlink TBF(s) for the mobile station by sending on PACCH the PACKET DOWNLINK ASSIGNMENT, MULTIPLE TBF DOWNLINK ASSIGNMENT, PACKET TIMESLOT RECONFIGURE or MULTIPLE TBF TIMESLOT RECONFIGURE message with the Control Ack bit set to ‘1’ for each TBF. In case the network establishes a new downlink TBF for a mobile station that does not support multiple TBF procedures, or if EMST is used, reconfigures the ongoing TBF, the network shall stop timer T3193 for the TBF, or if EMST is used, for the associated RLC entity.

If the mobile station, after sending the (EGPRS) PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC message with the Final Ack Indicator bit set to ‘1’ for a given TBF, receives a PACKET DOWNLINK ASSIGNMENT, MULTIPLE TBF DOWNLINK ASSIGNMENT, PACKET TIMESLOT RECONFIGURE or MULTIPLE TBF TIMESLOT RECONFIGURE message with the Control Ack bit set to ‘1’ on the PACCH associated with this TBF while its timer T3192 is running, or if EMST is used, while the timer T3192 associated with the RLC entity identified by the TFI included in the message is running, the mobile station shall stop this instance of timer T3192, consider this downlink TBF, or if EMST is used, the associated RLC entity released and act upon the new assignments.

When timer T3192 expires then the mobile station shall release the related downlink TBF, or if EMST is used, the associated RLC entity. If there are no other ongoing TBF the mobile station in packet transfer mode or MAC-Shared state shall enter packet idle mode or MAC-Idle state; the mobile station in dual transfer mode or MAC-DTM state shall return to dedicated mode or MAC-Dedicated state. The DRX mode procedures shall be applied as specified in sub-clause 5.5.1.5. If there are one or more ongoing TBFs a mobile station shall remain in its current mode/state and can request additional uplink TBFs as follows:

– It may send a PACKET RESOURCE REQUEST message using the PACCH if there is at least one ongoing uplink TBF as described in sub-clause 8.1.1.1.2.

– It may include a Channel Request Description or the Extended Channel Request Description information element in the (EGPRS) PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message if there are no ongoing uplink TBFs and at least one ongoing downlink TBF as described in sub-clause 8.1.2.5.

9.3.4 Non-persistent mode operation

9.3.4.0 General

The transfer of RLC data blocks in RLC non-persistent mode includes non-exhaustive retransmissions. The block sequence number (BSN) in the RLC data block header is used to number the RLC data blocks for reassembly. When RLC non-persistent mode is used for an MBMS bearer the receiving side sends MBMS DOWNLINK ACK/NACK messages to inform the transmitting side of the status of the reception and to convey neighbouring cell measurements. When RLC non-persistent mode is used for an EGPRS TBF the receiving side sends a PACKET UPLINK ACK/NACK, an EGPRS PACKET DOWNLINK ACK/NACK, an EGPRS PACKET DOWNLINK ACK/NACK TYPE 2, an EGPRS PACKET DOWNLINK ACK/NACK TYPE 3 or EGPRS PACKET DOWNLINK ACK/NACK DLMC message to inform the transmitting side of the reception status.

9.3.4.1 Operation during an MBMS bearer

The mobile station receives RLC/MAC blocks on the assigned downlink PDCHs. On each assigned PDCH, the mobile station shall in the RLC/MAC header identify the MBMS_BEARER_ID within the TFI field and decode the RLC data blocks if the mobile station is monitoring that MBMS Bearer. The operation during the MBMS bearer shall be as defined in sub-clause 9.1

9.3.4.2 Release of an MBMS radio bearer

The network may initiate the normal or abnormal release of an MBMS radio bearer by transmitting a PACKET TBF RELEASE message to the mobile station(s) on the PACCH, as described in sub-clause 8.1.4.4.

The Final Block Indicator (FBI) bit shall not be set to the value ‘1’ in any RLC/MAC block for data transfer of the MBMS radio bearer.

9.3.4.3 Operation during an EGPRS TBF

The MAC procedures defined in sub-clause 8.1.1 and 8.1.2 apply for EGPRS TBFs that make use of RLC non-persistent mode. Release of an uplink EGPRS TBF operating in Non-persistent mode is specified in sub-clause 9.5. Release of a downlink EGPRS TBF operating in Non-persistent mode is as specified for RLC unacknowledged mode, (see sub-clause 9.3.3.5).

9.4 Abnormal release cases

9.4.1 Abnormal release with access retry

The procedure for abnormal release with access retry is defined in sub-clause 8.7.2.

9.4.2 Abnormal release with cell reselection

If the mobile station is not in dedicated mode of a circuit switched connection, or is in MAC-Shared state, the mobile station shall abort all TBFs in progress and return to packet idle mode or MAC-Idle state. The mobile station shall perform an abnormal cell reselection (see 3GPP TS 45.008) and initiate the establishment of one or more uplink TBFs, using the procedures on CCCH or PCCCH as defined in sub-clause 7.1 on the new cell. The mobile station shall not reselect back to the original cell for T_RESEL seconds if another suitable cell is available.

If the abnormal cell reselection is abandoned (see 3GPP TS 45.008), the mobile station shall report an RLC/MAC failure to upper layers. If the mobile station remains in the cell where the abnormal release occurred, the DRX mode procedures shall be applied, as specified in sub-clause 5.5.1.5.

If the mobile station is in dedicated mode of a circuit switched connection (applies in GPRS class A mode of operation) or is in MAC-DTM state, the mobile station shall perform an abnormal release without retry, defined in sub-clause 8.7.1.

The parameter T_RESEL (default value 5 s) is broadcast in PSI 3.

9.5 Uplink TBF release in extended uplink TBF mode

In the extended uplink TBF mode (see sub-clause 9.3.1b), the network may initiate the release an uplink TBF by sending a PACKET UPLINK ACK/NACK message with the Final Ack Indicator set to ‘1’. The network shall include a valid RRBP field in the RLC/MAC control block header and clear counter N3103 for the TBF. The network may use the TBF Est field in the PACKET UPLINK ACK/NACK message to allow the mobile station to request the establishment of new TBF. The release of the uplink TBF, using this procedure, may be initiated at a point determined by the network.

In case EMST is used, the network shall release an uplink TBF by releasing all the RLC entities allocated on that uplink TBF. The uplink TBF is successfully released when the last RLC entity is released. The network shall perform the release of an RLC entity as specified in this sub-clause.

If the PACKET UPLINK ACK/NACK message has the Final Ack Indicator bit set to ‘1’ and the following conditions are fulfilled: TBF Est field is set to ‘1’; the mobile station has new data to transmit; the mobile station has no other ongoing TBFs, or if EMST is used, no other active RLC entity, the mobile station shall release the uplink TBF and may request the establishment of a new TBF using one of the following procedures:

If the PACKET UPLINK ACK/NACK message has the Final Ack Indicator bit set to ‘1’ and the mobile station does not initiate the establishment of a new uplink TBF according to one of the procedures described above, the mobile station shall transmit the PACKET CONTROL ACKNOWLEDGEMENT message and release the TBF, or if EMST is used, the RLC entity. If there are no other ongoing TBFs, or if EMST is used, no other ongoing RLC entities, the mobile station in packet transfer mode shall return to packet idle mode; the mobile station in dual transfer mode shall return to dedicated mode. The DRX mode procedures shall be applied as specified in sub-clause 5.5.1.5. If there are one or more ongoing TBFs a mobile station shall remain in its current mode/state and can request additional uplink TBFs as follows:

– It may send a PACKET RESOURCE REQUEST message using the PACCH if there is at least one ongoing uplink TBF as described in sub-clause 8.1.1.1.2.

– It may include a Channel Request Description or the Extended Channel Request Description information element in the (EGPRS) PACKET DOWNLINK ACK/NACK message or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message or a Channel Request Description information element in the EGPRS PACKET DOWNLINK ACK/NACK DLMC message if there are no ongoing uplink TBFs and at least one ongoing downlink TBF as described in sub-clause 8.1.2.5.

When the network receives the PACKET CONTROL ACKNOWLEDGEMENT message or the PACKET RESOURCE REQUEST message in the radio block indicated by the RRBP field, it may reuse the TFI and USF resources. If EMST is used, the USF resources may be reused only if the TBF is released, i.e. the last RLC entity allocated on the uplink TBF is released.

When EMST is not used or when EMST is used and the last RLC entity is released, if the network receives the PACKET CONTROL ACKNOWLEDGEMENT message with Ctrl Ack bits set to ’00’ or the PACKET RESOURCE REQUEST message in the radio block indicated by the RRBP field and the network has set the TBF Est field to ‘1’ in the PACKET UPLINK ACK/NACK message, the network shall follow one of the following procedures:

– In case the mobile station requested the establishment of new TBF with the PACKET CONTROL ACKNOWLEDGEMENT message, the network shall respond to the mobile station with the PACKET UPLINK ASSIGNMENT message including Single Block Allocation structure or the PACKET ACCESS REJECT message on the same PDCH as the mobile station has sent the PACKET CONTROL ACKNOWLEDGEMENT message. TLLI shall be used to identify the mobile station. The network shall use the same procedures as are used for TBF establishment using two phase access described in sub-clause 7.1.3 starting from the point where the network transmits the PACKET UPLINK ASSIGNMENT message including Single Block Allocation structure or the PACKET ACCESS REJECT message.

– In case the mobile station requested the establishment of new TBF with the PACKET RESOURCE REQUEST message, the network shall use the same procedures as are used for TBF establishment using two phase access described in sub-clause 7.1.3 starting from the point where the network has received the PACKET RESOURCE REQUEST message. TLLI shall be used to identify the mobile station.

If the network does not receive the PACKET CONTROL ACKNOWLEDGEMENT message or the PACKET RESOURCE REQUEST message for the TBF, or if EMST is used, for the RLC entity in the radio block indicated by the RRBP field, it shall increment counter N3103 and retransmit the PACKET UPLINK ACK/NACK message for the TBF, or if EMST is used, the RLC entity. When EMST is not used or when EMST is used and the last RLC entity is released, if counter N3103 exceeds its limit, the network shall stop scheduling new uplink resources for the TBF, stop sending the PACKET UPLINK ACK/NACK message to the mobile station and start timer T3169 for the TBF.

When timer T3169 expires for the TBF, the network may reuse the TFI and USF resources. If EMST is used for the TBF, the USF resources may be reused only once the TBF is released, i.e. the last RLC entity allocated on the uplink TBF is released.