9.13 CS Channel Modification

3GPP43.318Generic Access Network (GAN)Release 16Stage 2TS

The GANC may initiate the CS channel modification procedure when it determines that one or more active CS channels require modification; e.g., based on information received from the MSC in the RAB Assignment Request message or based on local GANC logic. For example, the GANC may initiate this procedure if it detects "packet loss" and handover to GERAN/UTRAN is not possible or desired. CS channel modification and PTC modification use the same messages and the same basic message flows, but differ in the content of the messages.

The GANC may modify the following parameters:

– RAB Configuration

– Sample Size

– RTP UDP Port

– GANC IP Address

– Multi-rate Configuration 2

– RTP Redundancy Configuration

– NAS Synchronisation Indicator

– RTCP UDP Port

Figure 54: CS Channel Modification

1. A call is established as described in clauses 9.10 or 9.11.

2. The GANC sends the GA-RRC MODIFY CHANNEL message to the MS to modify parameters for the established call.

3. The MS responds with the GA-RRC MODIFY CHANNEL ACKNOWLEDGE message to the GANC.