11.2.51 EC 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

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

This message is sent on the EC-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 by including the EC Channel Request Description in the message.

Message type: EC Packet Downlink Ack/Nack

Direction: mobile station to network

Table 11.2.51.1: EC Packet Downlink Ack/Nack information elements

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

< DOWNLINK_TFI : bit (5) >

< MS OUT OF MEMORY : bit(1)>

{ 0 < EC Ack/Nack Description : < EC Ack/Nack Description IE >> — Final Ack Indicator = 0

| 1 — Final Ack Indicator = 1 }

{ 0

| 1 { < EC Channel Quality Report : < EC Channel Quality Report IE > >

< DL_CC_EST : bit (4) > } }

{ 0 | 1 < EC Channel Request Description : < EC Channel Request Description struct > > }

{ — Rel-14 extension

{ 0 | 1 < MS Transmission Offset : bit (4) >

< MS Sync Accuracy : bit (4) > }

}

<padding bits >;

< EC Channel Request Description struct > ::=

< PRIORITY : bit (1) >

< NUMBER_OF_UL_DATA_BLOCKS : bit (4) >;

Table 11.2.51.2: EC 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.

EC Ack/Nack Description IE
This information element is defined in sub-clause 12.72.

EC Channel Quality Report IE
This information element is defined in sub-clause 12.75.

MS OUT OF MEMORY (1 bit field)
This field indicates if the MS no more has enough memory to perform Incremental Redundancy.

0 The MS has enough memory
1 The MS is running out of memory

PRIORITY
This field indicates the priority of the transfer for which the mobile station is requesting uplink resources.

0 Normal priority
1 High priority

NUMBER_OF_UL_DATA_BLOCKS
This field indicates the number of UL RLC Data blocks, using MCS-1, that are requested by the mobile station. The field is coded as shown in the following table:

bit
4 3 2 1
0 0 0 0 1 RLC data block
0 0 0 1 2 RLC data blocks
. . .
1 1 1 0 15 RLC data blocks
1 1 1 1 >15 RLC data blocks

DL_CC_EST (4 bit field)
This field contains the latest downlink Coverage Class estimation and the latest estimated C value range in case the C value is above BT_Threshold_DL, see 3GPP TS 45.008. The BT_Threshold_DL value is broadcast in EC SI 2, see 3GPP TS 44.018. The DL_CC_EST field shall be set according to the following table:

bit

4 3 2 1

0 0 0 0 DL CC4

0 0 0 1 DL CC3

0 0 1 0 DL CC2

0 0 1 1 DL CC1; BT_Threshold_DL ≤ C Value < BT_Threshold_DL+3 dB
0 1 0 0 DL CC1; BT_Threshold_DL+3 dB ≤ C Value < BT_Threshold_DL+6 dB
0 1 0 1 DL CC1; BT_Threshold_DL+6 dB ≤ C Value < BT_Threshold_DL+9 dB
0 1 1 0 DL CC1; BT_Threshold_DL+9 dB ≤ C Value < BT_Threshold_DL+12 dB
0 1 1 1 DL CC1; BT_Threshold_DL+12 dB ≤ C Value < BT_Threshold_DL+15 dB
1 0 0 0 DL CC1; BT_Threshold_DL+15 dB ≤ C Value < BT_Threshold_DL+18 dB
1 0 0 1 DL CC1; BT_Threshold_DL+18 dB ≤ C Value < BT_Threshold_DL+21 dB
1 0 1 0 DL CC1; BT_Threshold_DL+21 dB ≤ C Value < BT_Threshold_DL+24 dB
1 0 1 1 DL CC1; BT_Threshold_DL+24 dB ≤ C Value < BT_Threshold_DL+27 dB
1 1 0 0 DL CC1; BT_Threshold_DL+27 dB ≤ C Value < BT_Threshold_DL+30 dB
1 1 0 1 DL CC1; BT_Threshold_DL+30 dB ≤ C Value < BT_Threshold_DL+33 dB
1 1 1 0 DL CC1; BT_Threshold_DL+33 dB ≤ C Value < BT_Threshold_DL+36 dB
1 1 1 1 DL CC1; BT_Threshold_DL+36 dB ≤ C Value < BT_Threshold_DL+39 dB

MS Transmission Offset (4 bit field)

If a downlink EC TBF is established using a downlink assignment message indicating “MS Transmission Offset” and “MS Sync Accuracy” parameters are needed then this field is included (see sub-clause 8.1.2.2a). It is coded as decribed in sub-clause 10.4.33.

MS Sync Accuracy (4 bit field)