11.2.6 Packet Downlink Ack/Nack

04.603GPPGeneral Packet Radio Service (GPRS)Mobile Station (MS) - Base Station System (BSS) interfaceRadio Link Control / Medium Access Control (RLC/MAC) protocolRelease 1999TS

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) > }

< 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.

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.

C_VALUE (6 bit field)
This field is encoded as the binary representation of the C value as specified in 3GPP TS 05.08.
Range 0 to 63

RXQUAL (3 bit field)
This field contains the RXQUAL parameter field calculated by the mobile station (see 3GPP TS 05.08). This field is encoded as defined in 3GPP TS 04.08.
Range 0 to 7

PFI (7 bit field)
This field contains the PFI parameter identifying a Packet Flow Context. The PFI parameter is encoded as the contents of the PFI information element as defined in 3GPP TS 24.008. 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.

SIGN_VAR (6 bit field)
This field contains the signal variance parameter SIGN_VAR calculated by the mobile station (see 3GPP TS 05.08).

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 05.08 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