6.10 Relocation during TrFO towards GERAN Iu-mode

23.1533GPPOut of band transcoder controlRelease 17Stage 2TS

Figure 6.10/1: Configuration during intra-MSC SRNS Relocation towards GERAN Iu-mode

The description of Figure 6.2/1 (Configuration during intra-MSC SRNS Relocation) within clause 6.2 applies for the network and protocol entities involved in the Relocation towards GERAN Iu-mode scenario with following modifications:

RAN node A either is a RNC or a BSC. In the latter case BSC-A acts as a RNC-A.

BSC-A’ acts as a RNC-A’.

Therefore Figures 6.2/2 to 6.2/3. (the respective message flows for SRNS Relocation and TrFO) apply as well with the appropriate modifications outlined below:

Relocation Initiation

If the MSC-Server-A received the GERAN capabilities of the target cell within the RANAP Relocation Required message (for details when the capabilities are included see [16]), MSC-Server-A shall compare these capabilities with the current Selected Codec (BICC) and the Available Codecs List (BICC), taking into account Supported Codec Set and Active Codec Set for adaptive multimode codecs. If the GERAN capabilities in terms of codec types and modes for adaptive multimode codecs do not include all codes types and modes in the Available Codecs List (BICC) and all modes and the type of the Selected Codec (BICC), MSC Server A shall invoke the appropriate of the modification procedures in clause 5.8. Criteria for the selection of the appropriate procedure are given in clause 5.8. Upon completion of this procedure, or if no modification procedure is required, MSC server A shall proceed with the Relocation procedure as described in Figure 6.2/2 to 6.2/3 (Step 2. to 17.).

RAB Assignment on the new Iu leg:

RAB Assignment on the new Iu leg shall be performed as described in clause 6.2 with following modifications:

The Relocation Request (Step 3.) contains possibly new RAB parameters depending on the actions executed as outlined above during the Relocation Initiation phase according to the decision on the selected codec as well as on the selected codec modes (for an adaptive multi-rate codec type). In addition, the MSC-Server-A shall include the selected codec type within Relocation Request message. For definition of list of supported codec type see [15].