9.1.64 EC DOWNLINK ASSIGNMENT

3GPP44.018GSM/EDGE Radio Resource Control (RRC) protocolMobile radio interface Layer 3 specificationRelease 17TS

This message is sent on the EC-CCCH by the network to assign downlink packet resources to a mobile station that has enabled EC operation.

Message type: EC DOWNLINK ASSIGNMENT

Significance: dual

Direction: network to mobile station

Table 9.1.64.1: EC DOWNLINK ASSIGNMENT message content

< EC Downlink Assignment message content > ::=

< Message Type : bit (4) >

< Used DL Coverage Class: bit (2) >

{ 0 | 1 < EC Page Extension : bit (4) > }

< TLLI : bit (32) >

< EC Packet Channel Description Type 2 : bit (15) >

< EC Downlink Allocation : < EC Downlink Allocation struct >>

— Additions in release Rel-14:

< Multilateration Information Request : bit (1) >

<spare padding> ;

< EC Downlink Allocation struct > ::=

< Timing Advance : bit (6) >

< STARTING_DL_TIMESLOT : bit (3) >

< Downlink_TFI_Assignment : bit (5) >

< TIMESLOT_MULIPLICATOR : bit (2) >

< STARTING_UL_TIMESLOT_OFFSET (2) >

< GAMMA : bit (5) >

< ALPHA Enable : bit (1) >

{ 0 | 1 < P0 : bit (4) >

< PR_MODE : bit (1) > } ;

Table 9.1.64.2: EC DOWNLINK ASSIGNMENT message details

Message Type (4 bit field)

This field indicates the type of message sent on the EC-CCCH (see Table 10.4.4)

Used DL Coverage Class (2 bit field)

This field is coded as described in sub-clause 9.1.60.

EC Page Extension (4 bit field)

This field is coded as described in sub-clause 9.1.60.

TLLI (32 bit field)

This field is the binary representation of a TLLI. The coding of TLLI is left open for each administration using the structure specified in 3GPP TS 23.003.

EC Packet Channel Description Type 2 (15 bit field)

This information element is coded as described in sub-clause 10.5.2.85

Timing Advance (6 bit field)

This field is coded as described in sub-clause 9.1.60

STARTING_DL_TIMESLOT (3 bit field)

This field indicates the first assigned timeslot within the set of assigned downlink timeslots.:

Bit

3 2 1

0 0 0 Timeslot 0 is the first assigned downlink timeslot

0 0 1 Timeslot 1 is the first assigned downlink timeslot

0 1 0 Timeslot 2 is the first assigned downlink timeslot

0 1 1 Timeslot 3 is the first assigned downlink timeslot

1 0 0 Timeslot 4 is the first assigned downlink timeslot

1 0 1 Timeslot 5 is the first assigned downlink timeslot

1 1 0 Timeslot 6 is the first assigned downlink timeslot

1 1 1 Timeslot 7 is the first assigned downlink timeslot

If the field EC_Reduced_PDCH_Allocation is set to 0 in the EC SYSTEM INFORMATION TYPE 2 message (see sub-clause 9.1.43q): A mobile station using CC2, CC3 or CC4 on the downlink is always assigned 4 consecutive timeslots and therefore only timeslot 0, 1, 2, 3 or 4 shall be indicated as the first assigned downlink timeslot.

If the field EC_Reduced_PDCH_Allocation is set to 1 in the EC SYSTEM INFORMATION TYPE 2 message (see sub-clause 9.1.43q): A mobile station using CC2, CC3 or CC4 on the downlink is always assigned 2 consecutive timeslots and therefore only timeslot 0, 1, 2, 3, 4, 5 or 6 shall be indicated as the first assigned downlink timeslot.

Downlink_TFI_Assignment (5 bit field)

This field is the binary representation of the Temporary Flow Identity, see 3GPP TS 44.060. Range: 0 to 31.

TIMESLOT_MULTIPLICATOR (2 bit field)
This field defines how many downlink timeslots the assignment contains when the assigned downlink Coverage Class is CC1. The field is coded as follows:

bit

2 1

0 0 1 timeslot assigned

0 1 2 timeslots assigned

1 0 3 timeslots assigned

1 1 4 timeslots assigned

Values other than ‘00’ can only be used if supported by the mobile station, as indicated by its multislot capability, see 3GPP TS 45.002 [32]. If the assigned downlink Coverage Class > CC1 (see the EC Packet Channel Description Type 2 field), the mobile station shall consider the TIMESLOT_MULTIPLICATOR field as invalid.

STARTING_UL_TIMESLOT_OFFSET (2 bit field)
This field defines the timeslot number of the lowest timeslot included in the assignment that is used for transfer of uplink RLC/MAC control messages on the EC-PACCH during the DL EC TBF. The number of additional timeslots that are included in the uplink assignment depends on the assigned UL Coverage Class. The assigned timeslots are contiguous, starting with the timeslot number indicated in the STARTING_UL_TIMESLOT_OFFSET field. The STARTING_UL_TIMESLOT_OFFSET field is encoded as an offset to the timeslot assigned with the STARTING_DL_TIMESLOT field. The encoding of the field is dependent of the value of the DL_COVERAGE_CLASS and UL_COVERAGE_CLASS fields in the same message.

If both DL_COVERAGE_CLASS and UL_COVERAGE_CLASS > CC1, the same timeslots are assigned in both the uplink and the downlink directions. The STARTING_UL_TIMESLOT_OFFSET field can then be considered as not valid by the mobile station.

If DL_COVERAGE_CLASS = CC1 and UL_COVERAGE_CLASS > CC1, the STARTING_UL_TIMESLOT_OFFSET field is encoded according to the following code points if the field EC_Reduced_PDCH_Allocation is set to 0 in the EC SYSTEM INFORMATION TYPE 2 message (see sub-clause 9.1.43q). If the field EC_Reduced_PDCH_Allocation is set to 1 only the first two code points of the following shall be used:

bit

2 1

0 0       Same timeslot as indicated by STARTING_DL_TIMESLOT

0 1       STARTING_DL_TIMESLOT – 1

1 0       STARTING_DL_TIMESLOT – 2

1 1       STARTING_DL_TIMESLOT – 3

If DL_COVERAGE_CLASS > CC1 and UL_COVERAGE_CLASS = CC1, the STARTING_UL_TIMESLOT_OFFSET field is encoded according to the following code points if the field EC_Reduced_PDCH_Allocation is set to 0 in the EC SYSTEM INFORMATION TYPE 2 message (see sub-clause 9.1.43q). If the field EC_Reduced_PDCH_Allocation is set to 1 only the first two code points of the following shall be used:

bit

2 1

0 0       Same timeslot as indicated by STARTING_DL_TIMESLOT

0 1       STARTING_DL_TIMESLOT + 1

1 0       STARTING_DL_TIMESLOT + 2

1 1       STARTING_DL_TIMESLOT + 3

If both DL_COVERAGE_CLASS and UL_COVERAGE_CLASS = CC1 (indicated by the EC Packet Channel Description Type 2 IE – see sub-clause 10.5.2.85), the uplink EC-PACCH is assigned to the timeslot indicated by the STARTING_DL_TIMESLOT field. In this case the STARTING_UL_TIMESLOT_OFFSET field is considered as invalid by the mobile station.

GAMMA (5 bit field)

This field is the binary representation of the parameter CH for MS output power control in units of 2 dB, see 3GPP TS 45.008.

ALPHA Enable (1 bit field)

This field is coded as described in sub-clause 9.1.60

P0 (4 bit field)

For description and encoding, see the Packet Uplink Assignment message in 3GPP TS 44.060.

PR_MODE (1 bit field)

For description and encoding, see the Packet Uplink Assignment message in 3GPP TS 44.060.

Multilateration Information Request (1 bit field)

This field indicates whether or not a MS is to include "MS Transmission Offset" and "MS Sync Accuracy" parameters when sending an EC Packet Downlink Ack/Nack message (see 3GPP TS 44.060 [76]) during a downlink EC TBF. This field is coded as follows:

0 Do not include "MS Transmission Offset" and "MS Sync Accuracy" parameters

1 Include the "MS Transmission Offset" and "MS Sync Accuracy" parameters