11.2.22 Packet System Information Type 4

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 optionally sent by the network on the PBCCH and PACCH giving information directing the mobile station to make interference measurements. This message shall not be segmented across more than one RLC/MAC control block by using the procedures specified in sub-clause 9.1.12a. Special requirements for the transmission of this message apply on PBCCH, see 3GPP TS 05.02.

Message type: PACKET SYSTEM INFORMATION TYPE 4

Direction: network to mobile station

Classification: distribution message

Table 11.2.22.1: PSI4 information elements

< PSI4 message content > ::=

< PAGE_MODE : bit (2) >

< PSI4_CHANGE_MARK : bit (2) >

< PSI4_INDEX : bit (3) >

< PSI4_COUNT : bit (3) >

< INT_MEAS_CHANNEL_LIST: < Channel List struct > >

< padding bits >

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

< Channel List struct > ::=

< Channel group struct >

{ 1 < Channel group struct > } ** 0 ;

< Channel Group struct > ::=

{ 0 < ARFCN : bit (10) >

| 1 < MA_NUMBER : bit (4) >

< MAIO : bit (6) > }

< TIMESLOT_ALLOCATION : bit (8) > ;

Table 11.2.22.1: PSI4 information element details

The PSI4 message is optional and is only sent if indicated by the Power Control parameter INT_MEAS_CHANNEL_LIST_AVAIL (see sub-clause 12.9).

Depending on the size of the list more than one PSI4 messages can be required to broadcast the total list. The PSI4 count parameter therefore indicates the last (highest indexed) PSI4 message. The sequence number of each PSI4 message is then indicated by the Message Sequence number parameter.

The PSI4 message contains a list of channels which shall be used by the mobile station for interference measurements in packet idle mode (se 3GPP TS 05.08). The channel list is defined by a Channel list struct which contains one or more Channel Group struct. The Channel Group struct can have two alternative coding formats, the MA format or the ARFCN format. The MA format shall be used for frequency hopping physical channels. At maximum 32 Channel Group structs may be defined, and of these at maximum 4 Channel Group structs may be defined in MA format.

Using the MA format, a set of physical channels may be defined. The definition comprises a mobile allocation specified in the PSI2 message and referenced by the MA_NUMBER value, a MAIO value and a TIMESLOT_ALLOCATION bit map.

Using the ARFCN format, a set of non-hopping physical channels may be defined by a ARFCN value, identifying the radio frequency, and a TIMESLOT_ALLOCATION bit map.

PSI4_CHANGE_MARK (2 bit field)
The PSI4 change mark field is changed each time information has been updated in any of the individual PSI4 messages. A new value indicates that the mobile station shall re-read the information from all PSI4 messages. The coding of this field is network dependent.
Range: 0 – 3.

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

PSI4_COUNT (3 bit field)
The PSI4 count field is coded as the binary representation of the last (highest indexed) individual PSI4 message.
Range: 0 – 7.

PSI4_INDEX (3 bit field)
The PSI4 index field is used to distinguish individual PSI4 messages. The field can take the binary representation of the values 0 to n, where n is the index of the last PSI4 message. (PSI4 count).
Range: 0 – 7.

ARFCN (Absolute RF channel number) (10 bit field)
The ARFCN is coded as the binary representation of the absolute RF channel number (see 3GPP TS 05.05).
Range: 0 to 1023.

MA_NUMBER (4 bit field)
The purpose of the MA_NUMBER field is to refer to a mobile allocation and a corresponding HSN value defined in the set of PSI2 messages for the decoding of a physical channel description. The MA_NUMBER field is binary coded.
Range: 0 to 13. (MA_NUMBER = 14 and 15 shall not be used in this message.)

MAIO (Mobile allocation index offset) (6 bit field)
The MAIO field is coded as the binary representation of the mobile allocation index offset as defined in 3GPP TS 05.02. Range: 0 to 63.

TIMESLOT_ALLOCATION (8 bit field)
This field is defined in sub-clause 12.18.