11.2.17a Packet Serving Cell Data

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

This optional message is sent by the network on the PACCH to provide system information broadcast on the BCCH (respectively PBCCH to a mobile station. For example, several instances of this message may be sent by the network in a cell supporting PACKET SI STATUS (respectively PACKET PSI STATUS) following the request for acquisition of system information by a mobile station. This message shall not be segmented across more than one RLC/MAC control block. If not all information fits into one instance of the PACKET SERVING CELL DATA message, the message can be repeated.

Message type: PACKET SERVING CELL DATA

Direction: network to mobile station

Classification: non-distribution message

Table 11.2.17a.1: Packet Serving Cell Data information elements

< Packet Serving Cell Data message content > ::=

< PAGE_MODE : bit (2) >

{ 0 < Global TFI : < Global TFI IE > >

{ < spare : bit (4) >

< CONTAINER_INDEX : bit (5) >

< CONTAINER : < Container repetition struct > >

< padding bits >

! < Non-distribution part error : bit (*) = < no string > > }

! < Address information part error : bit (*) = < no string > > }

! < Distribution part error : bit (*) = < no string > > ;

< Container repetition struct > ::=

{

{ < PD : bit (3) >

< CD_LENGTH : { bit (5) exclude 00000 exclude 11111 } >

< CONTAINER_DATA : octet (val(CD_LENGTH)) > — Final container segment. Next container follows.

| < PD : bit (3) >

< CD_LENGTH : { bit (5) == 11111 } >

< CONTAINER_DATA : octet ** > } ** — Container continued in next message.

{ < spare bit (3) > — Repetition continues until:

< CD_LENGTH : { bit (5) == 00000 } > } — A) val(CD_LENGTH) = 0 or

} // ; — B) end of PSCD message.

Table 11.2.17a.2: Packet Serving Cell Data information element details

The Packet Serving Cell Data message consists of up to 32 instances and contains serving cell system information messages from the BCCH or from the PBCCH or from both. Each container repetition struct contains information from one or more SI/PSI message. One SI/PSI message can be distributed over more than one instance.

A container can only refer to the serving cell.

PAGE_MODE (2 bit field)
This field is defined in sub-clause 12.20.

Global TFI
This information element contains the TFI of the mobile station’s downlink TBF or uplink TBF. This field is defined in sub-clause 12.10.

PD (3 bit field)
This field contains a protocol discriminator and indicates the origin of the contained message.

Bit
2 1
0 0 0 BCCH (LAPDm);
0 0 1 PBCCH (RLC/MAC);
0 1 0 Reserved; If received the contents of the container shall be discarded.
……
1 1 1 Reserved; If received the contents of the container shall be discarded.

CD_LENGTH (5 bit field)
This field indicates the number of CONTAINER DATA octets that forms a specific SI/PSI message and is coded as shown below.

Bit

5 4 3 2 1

0 0 0 0 0 No CONTAINER DATA follows; Spare padding is used to fill the rest of the message;

0 0 0 0 1 CONTAINER DATA length = 1 octet;

….

1 0 0 1 0 CONTAINER DATA length = 18 octets;

1 1 1 1 1 The remaining portion of the Packet Serving Cell Data message is used by the associated CONTAINER DATA. The message continues in a subsequent instance of the Packet Serving Cell Data message, in the next CONTAINER DATA with the same Protocol Discriminator value as the current one.

All other values reserved. If a reserved value is received the contents of the container shall be discarded.

CONTAINER_DATA(n*8 bits)

The concatenation of one or several CONTAINER_DATA octets forms the actual contents, specific to the SI/PSI messages.

If the contained system information messages are copied from the BCCH the information contained in the Packet Serving Cell Data message shall exclude the following information elements from the beginning of the messages: L2 Pseudo Length; RR management Protocol Discriminator and Skip Indicator.
If the contained system information messages are copied from the PBCCH the information contained in the Packet Serving Cell Data message shall include the complete PSI message.

Extra octets of padding bits at the end of the SI/PSI messages may be excluded.