11.2.6 Packet Downlink Ack/Nack

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

This message is sent on the PACCH from the mobile station to the network to indicate the status of downlink RLC data blocks received and to report the channel quality of the downlink. The mobile station may optionally initiate an uplink TBF.

Message type: PACKET DOWNLINK ACK/NACK

Direction: mobile station to network

Table 11.2.6.1: Packet Downlink Ack/Nack information elements

< Packet Downlink Ack/Nack message content > ::=

< DOWNLINK_TFI : bit (5) >

< Ack/Nack Description : < Ack/Nack Description IE > >

{ 0 | 1 < Channel Request Description : < Channel Request Description IE > > }

< Channel Quality Report : < Channel Quality Report struct > >

{ null | 0 bit** = <no string> — Receiver backward compatible with earlier version

| 1 — Additional contents for Release 1999

{ 0 | 1 < PFI : bit(7) > }

{ null | 0 bit** = < no string > — Receiver backward compatible with earlier version

| 1 — Additions for REL-5

{ 0 | 1 < Iu mode Channel Request Description : < Iu mode Channel Request Description IE > > }

{ 0 | 1 < RB Id : bit (5) > }

{ 0 | 1 < Timeslot Number : bit (3) > }

{ null | 0 bit** = <no string> — Receiver backward compatible with earlier version

| 1 — Additional contents for Release 6

{ 0 | 1 < Extended Channel Request Description : < Extended Channel Request Description IE > > } }

{ null | 0 bit** = <no string> — Receiver backward compatible with earlier version

| 1 — Additional contents for Release 7

< EARLY_TBF_ESTABLISHMENT : bit (1) >

< padding bits > } } };

< Channel Quality Report struct > ::=

< C_VALUE : bit (6) >

< RXQUAL : bit (3) >

< SIGN_VAR : bit (6) >

{ 0 | 1 < I_LEVEL_TN0 : bit (4) > }

{ 0 | 1 < I_LEVEL_TN1 : bit (4) > }

{ 0 | 1 < I_LEVEL_TN2 : bit (4) > }

{ 0 | 1 < I_LEVEL_TN3 : bit (4) > }

{ 0 | 1 < I_LEVEL_TN4 : bit (4) > }

{ 0 | 1 < I_LEVEL_TN5 : bit (4) > }

{ 0 | 1 < I_LEVEL_TN6 : bit (4) > }

{ 0 | 1 < I_LEVEL_TN7 : bit (4) > } ;

Table 11.2.6.2: Packet Downlink Ack/Nack information element details

DOWNLINK_TFI (5 bit field)
This field contains the TFI of the mobile station’s downlink TBF. This field is defined in sub-clause 12.15. On DBPSCH, this field equals the radio bearer identity of the radio bearer to which this message applies.

Ack/Nack Description
This information element is defined in sub-clause 12.3.

Channel Request Description
This information element is defined in sub-clause 12.7. If a PFI field is included in this message, it relates to the TBF request contained in the Channel Request Description IE. Neither this IE nor the PFI field shall be included if the Extended Channel Request Description IE is included.

Iu mode Channel Request Description
This information element is defined in sub-clause 12.7a.

Extended Channel Request Description
This information element is defined in sub-clause 12.7b. This IE contains a request for one or more additional uplink TBFs and shall only be included if the mobile station and the network support multiple TBF procedures. If this IE is included, the Channel Request Description IE and PFI field in the message shall be omitted.

C_VALUE (6 bit field)
This field is encoded as the binary representation of the C value as specified in 3GPP TS 45.008.
Range 0 to 63

RXQUAL (3 bit field)
This field contains the RXQUAL parameter field calculated by the mobile station (see 3GPP TS 45.008). This field is encoded as defined in 3GPP TS 44.018.
Range 0 to 7

PFI (7 bit field)
This field contains the PFI parameter identifying a Packet Flow Context relating to the resource request specified in the Channel Request Description IE. The PFI parameter is encoded as the contents of the PFI information element as defined in 3GPP TS 44.018. This field may be included if the network supports packet flow context procedures and if a Channel Request Description IE is included in the message. If this field is included but the Channel Request Description IE is omitted, this field shall be ignored.

SIGN_VAR (6 bit field)
This field contains the signal variance parameter SIGN_VAR calculated by the mobile station (see 3GPP TS 45.008).

bit
6 5 4 3 2 1
0 0 0 0 0 0 0dB2 to 0.25 dB2
0 0 0 0 0 1 >0.25 dB2 to 0.50 dB2
0 0 0 0 1 0 >0.50 dB2 to 0.75 dB2
: : : : :
1 1 1 1 1 0 >15.50 dB2 to 15.75 dB2
1 1 1 1 1 1 >15.75 dB2

I_LEVEL_TN0 (4 bit field)
I_LEVEL_TN1 (4 bit field)
I_LEVEL_TN2 (4 bit field)
I_LEVEL_TN3 (4 bit field)
I_LEVEL_TN4 (4 bit field)
I_LEVEL_TN5 (4 bit field)
I_LEVEL_TN6 (4 bit field)
I_LEVEL_TN7 (4 bit field)
These fields contain the I_LEVEL value measured on timeslots 0 through 7, respectively. The I_LEVEL is defined in 3GPP TS 45.008 and the coding of I_LEVEL is as follows:

bit
4 3 2 1
0 0 0 0 I_LEVEL 0
0 0 0 1 I_LEVEL 1
. . .
1 1 1 0 I_LEVEL 14
1 1 1 1 I_LEVEL 15

RB Id (5 bit field)
This field contains the radio bearer identity of the mobile station’s radio bearer for which the downlink data transfer on SFACCH is acknowledged. This field is not included when the PACKET DOWNLINK ACK/NACK messsage is sent on DBPSCH. This field is encoded as a binary number with range 0-31

Timeslot Number (3 bit field)
It contains the timeslot number of the timeslot on which the corresponding RRBP was received. This field shall be included if and only if the timeslot number of the PDTCH/SBPSCH on which the PACKET DOWNLINK ACK/NACK message is sent is different from the timeslot number of each of the timeslots assigned to this TBF in the direction of this TBF. This field is encoded as the binary representation of the timeslot number as defined in 3GPP TS 45.002.

EARLY_TBF_ESTABLISHMENT (1 bit field)

This field indicates whether or not the channel request is meant to request pre-allocatation of an uplink TBF:

0 The channel request is not meant to pre-allocate an uplink TBF.
1 The channel request is meant to pre-allocate an uplink TBF.