9.1.57 VGCS Neighbour Cell Information message

3GPP44.018GSM/EDGE Radio Resource Control (RRC) protocolMobile radio interface Layer 3 specificationRelease 17TS

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

The understanding of this message is only required for mobile stations supporting VGCS listening or VBS listening.

This message is sent on the main DCCH, in unacknowledged mode using the RR short protocol discriminator by the network to notify the mobile stations in on-going voice group calls of a change in the validity of information previously sent in System Information Type 10bis messages and/or System Information Type 10ter messages, which specify parameters for voice group calls in neighbouring cells.

Mobile stations not supporting VGCS listening or VBS listening shall ignore this message.

See table 9.1.57.1.

Message type: VGCS Neighbour Cell Information

Significance: dual

Direction: network to mobile station

Table 9.1.57.1: VGCS Neighbour Cell Information message content

<VGCS Neighbour Cell Information> ::=

<RR short PD : bit> — See 3GPP TS 24.007

<message type : bit(5)> — See 10.4

<short layer 2 header : bit(2)> — See 3GPP TS 44.006

< SI10bis Sequence : bit (2) > — new sequence number i

{ 0

{ 0 | 1 BSIC : bit (6) }

< Validity Information > } ** 1

{ 0 < SI10bis Neighbour Cell Info > } ** 1

<spare padding> ;

< Validity Information > ::=

{ 0 — information for this cell with sequence number i-1 is still valid

| 1 < Validity bitmap : bit (3) > }

Validity bitmap:

bit 0:

1 SI10bis information with sequence number i-1 is invalid

0 SI10bis information with sequence number i-1 is valid

bit 1:

1 SI10ter information with sequence number i-1 is invalid

0 SI10ter information with sequence number i-1 is valid

bit 2:

1 Group call is no longer active in neighbour cell

0 Group call is still active in neighbour cell

Validity Information is included for each neighbour cell, in order of increasing BCCH ARFCN (i.e. in the same order as used in SI10 Rest Octets, see sub-clause 10.5.2.44). If two or more neighbour cells have the same BCCH ARFCN then the BSIC shall be included to distinguish the cells.

If the group channel (either before or after a change) in a neighbouring cell is non-hopping, then bit 1 of the Validity bitmap shall be set to 1.

SI10bis Neighbour Cell Info is included for as many cells as possible for which bit 0 of the Validity bitmap is equal to 1 and bit 2 of the Validity bitmap is equal to 0, in the order in which the corresponding cells’ Validity Information was included.

If a mobile station receives a message including a Validity bitmap in which all 3 bits are set to 0, the mobile station shall diagnose an imperative message part error.