11.2.17 Packet PSI Status

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 which PSI messages the mobile station has received.

Message type: PACKET PSI STATUS

Direction: mobile station to network

Table 11.2.17.1: Packet PSI STATUS information elements

< Packet PSI Status message content > ::=

< GLOBAL_TFI : < Global TFI IE > >

< PBCCH_CHANGE_MARK : bit (3) >

< Received PSI Message List : < PSI Message List struct > >

< Received Unknown PSI Message List : < Unknown PSI Message List struct > >

< padding bits > ;

< PSI Message List struct > ::=

{ 1 < MESSAGE_TYPE : bit (6) >

< PSIX_CHANGE_MARK : bit (2) >

{ 0 | 1 < PSIX_COUNT : bit (4) >

< Instance bitmap : bit (val(PSIX_COUNT) + 1) > } } ** 0

< ADDITIONAL_MSG_TYPE : bit > ;

< Unknown PSI Message List struct > ::=

{ 1 < MESSAGE_TYPE : bit (6) > } ** 0

< ADDITIONAL_MSG_TYPE : bit > ;

Table 11.2.17.2: Packet PSI Status information element details

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

PBCCH_CHANGE_MARK (3 bit field)
This field is the binary representation of the last PBCCH_CHANGE_MARK received in the PSI1 message on PBCCH.

Received PSI Message List (construction)
This construction contains a list of correctly received PSI messages. In this version of the protocol, the following message types may be indicated in this list: PSI2 (highest priority), PSI3, PSI3bis, PSI4, PSI5, PSI3ter, PSI3quater, PSI6, PSI7 and PSI8 (lowest priority). The sender of this message may indicate as many messages in this list as can be fit into the message. Messages are listed by message type in descending order of priority. If there are more PSI messages than can be indicated in this list, the presence of additional message type(s) shall be indicated at the end of the list.

If the sender of this message has received a PSI message which is part of a consistent set of PSI messages (see sub-clause 5.5.2.1.4), the Instance Bitmap may indicate which instances of this message type that have been received.

Under certain circumstances, see sub-clause 5.5.1.4.3, the sender of this message may use this construction to indicate the message type of a PSI message that has not been received. In that case, the corresponding Instance Bitmap field shall be included. The PSIX_CHANGE_MARK field, PSIX_COUNT field and the one element of the Instance Bitmap field shall all be set to the value ‘0’.

Received Unknown PSI Message List (construction)
This construction contains a list of message types that are received on PBCCH, which are not recognized as a PSI message type. In this version of the protocol, any message type except PSI1, PSI2, PSI3, PSI3bis, PSI3ter, PSI3quater, PSI4, PSI5 , PSI6, PSI7 or PSI8 may be indicated in this list. The sender of this message may indicate as many messages in this list as can be fit into the message following the Received PSI Message List. Messages are listed by message type in the inverse order of reception, starting with the most recently received message type. If there are more messages than can be indicated in this list, the presence of additional message type(s) shall be indicated at the end of the list.

MESSAGE_TYPE (6 bit field)
This field is the binary representation of the message type (see sub-clause 11.2.0.1).

PSIX_CHANGE_MARK (2 bit field)
This field is the binary representation of the PSI change mark parameter received for a certain PSI message type.
Range: 0 to 3.

PSIX_COUNT (4 bit field)
This field is the binary representation of the PSI count parameter received for a certain PSI message type. This field indicates the length of the corresponding Instance bitmap field and shall be provided only if the corresponding Instance bitmap field is provided in the message.
Range: 0 to 7 or 0 to 15, depending on message type.

Instance bitmap (1 – 16 bit field)
This field is a bitmap indicating which instances of a certain message type that are received within a consistent set of PSI messages. This field shall be included when a sub-set of these messages has been received. This field shall not be included when the complete set of these messages has been received.

The most significant bit of this bitmap (bit N) refers to the message instance with the PSI index parameter = N–1, where N is the number of instances of the particular message type (PSI count + 1). The least significant bit of this bitmap (bit 1) refers to the message instance with the PSI index parameter = 0. Each bit position is coded:

0 Message instance is not received;
1 Message instance is received.

ADDITIONAL_MSG_TYPE (1 bit field)
0 No additional message type is present.
1 Additional message type(s) are present.