1. CDMA Systems Vocoder Placement Issues cdma VOCODER PLACEMENT ISSUES Ericsson CDMA Systems Roger Gustavsson Qiang Gao Ake Jansson

2. CDMA Systems Vocoder Placement Issues cdma Proposed Architecture Evolution CDMA SYSTEMS Vocoder Placement Issues MS Vocoder IS-95/2000 Signaling Msgs RAN MGW IP Network IS-95/2000 Signaling Msgs MSC Server Vocoder AxAx A1* PTSN MSC A2 A1 PTSN IP Transport for compressed voice

3. CDMA Systems Vocoder Placement Issues cdma Vocoder Placement Requirements For support of Multimedia mobiles the vocoders shall be located in the Media Gateway (MGW) For support of Legacy mobiles the vocoders can be located in the RAN or MGW IP Transport for compressed voice  evolution to All-IP Architecture  Smooth migration towards an unified IP transport platform for both voice and data Open Issues  header compression, e.g., RTP/UDP/IP header compression  Multiplexing at Link Layer e.g. PPP Mux  End to End Multiplexing at Application Layer

4. CDMA Systems Vocoder Placement Issues cdma Impact of Vocoder Placement in MGW New Protocol Stack (A2*) for compressed voice: IOS Application RTP/UDP/IP Link Layer Physical Layer QoS Requirements  current IP transport (IOS v4.1) supports best effort delivery.  need to provide guaranteed service Evolved signaling interface (A1*) to MSC server (to allow for resource allocation and management) New signaling interface between MSC server and MGW

5. CDMA Systems Vocoder Placement Issues cdma IS-95/2000 Signaling Issues related to Vocoder Placement Blank-and-Burst and V2 mode not affected Dim-and-burst  requires the vocoder to lower the coding rate upon request  Vocoder Rate Control In-band –use the 8 encoder tail bits –Same as the voice transport latency Out-of-band –Specify explicit signaling between BSC/MSC Server/MGW –signaling latency can be different than voice latency (additional complexity)  Latency requirements on IP transport imposed by air interface signaling delay requirements e.g. HHO to be completed within TBD msecs

6. CDMA Systems Vocoder Placement Issues cdma Roaming and Inter-operability Issues Handoff between legacy/evolved architecture  Handoff from legacy to evolved architecture will require changes to existing signaling procedures (e.g. target to specify vocoder assignment) Transcoding Issues  With support for EVRC/13K/SMV enhancements needed for TFO operation  Mobile to Mobile transcoding (selection of MGW i.e. edge of core network vs. interior to core network)