Interoperability & Global PoC Standards

Transcription

1 CDG Technology Forum CDMA PoC: Interoperability & Global PoC Standards Kalle Ahmavaara, Nokia, CDMA2000 Standardization 1 NOKIA San Diego, June 30 th, 2004

2 Interoperability between PoC Clients Example consumer PoC use cases: Family in the shopping mall or theme parks communicating plans Group searching a person or a location Discussing the game in a sports event A group coordinating where to meet for an evening out Teenagers organizing a party or calling friends during the party PoC chat groups The service acceptance and the resulting market size for all of the above is completely different with a globally interoperable solution! Anybody needs to be able to initiate PoC Session with anybody! 2 NOKIA

3 Two Methods for PoC Interoperability 1. Usage of a Common Global system Off-the-self, interoperable products from several vendors with competitive prices Lightest possible Network Functionality with no network media processing Backwards & forwards compatibility is taken care by the standard New features easy to introduce Poc with data, pictures, video... All interoperable immediately without any network changes Optimal quality of service 2. Signalling gateways & Media Transcoders Decreased quality of service Burden of specifying, implementing, operating and updating several PoC systems. No benefit from features that are not interoperable Complex and costly network with all the time increasing complexity Media packet processing in Nw Difficult introduction of new features Gateway may become a bottleneck & control point GW1 GW1 GW1 Usage of gateways & transcoders should be avoided whenever possible! 3 NOKIA

4 OMA PoC Standardization Wide commitment in Industry to OMA PoC work. PoC WG is chaired by T-Mobile and co-chaired by Sprint & Vodafone. Strong drive from carriers! OMA is committed to complete OMA PoC standard by the end of 2004 OMA produces following POC Specifications: OMA PoC Requirements Document (OMA PoC RD): Approved, Editor: Siemens OMA PoC Architecture Document (OMA PoC RD) : Final Review: Editor: Nokia OMA PoC Control Plane Specifications: Draft (~50% completed), Editor: RIM Specifies the usage of SIP signalling for OMA PoC OMA PoC User Plane specification: Draft (~50% completed), Editor: Ericsson Specifies the user plane (media, floor control, etc) for OMA PoC Full set of PoC specifications available December 2004 from OMA! 4 NOKIA

5 OMA Service Enablers and IMS/MMD Service Enablers PoC Downloading, Streaming, Messaging,... IMS/MMD Service Core Session Dynamic Subscription Control Management IP Connectivity Other Enablers Intelligent Charging Control ISC OMA SIP based service enablers (like PoC) are to be specified on top of a common IMS/MMD platform IMS/MMD platform provides e.g. following features: Routing and reachability Authentication and transitive trust Signaling compression Privacy User profile storage Charging, accounting Interface to the access network These wheels do not need to be invented for each new service! IMS Platform approach greatly reduces the OMA PoC Specification effort! 5 NOKIA

6 End-to-End PoC Codec: Impact to System Efficiency Different ways to optimize system capacity for different services: 1) Optimization for Traditional Conversational Speech: Optimized codecs for each radio interface. Each radio system has its own speech codecs optimized for the radio frame sizes 2) Optimization for PoC Traffic model is different from conversational speech Key optimization for PoC is the efficient packet based channel allocation - System capability to fast packet based channel allocation for each talk burst - System capability to allocate reverse and forward links separately User action Packet switched Circuit switched PTT button pressed / released / timer expiry Time (s) Reverse link resource reserved Forward Link resource reserved PoC should be kept as a generic IP service decoupled from air interfaces 6 NOKIA

7 End-to-End PoC Codec: User Point of View EVRC Half Rate and AMR 5,15 are typical PoC speech codecs for CDMA and GSM Listening Test Arranged to test the quality of end to end speech coding versus transcoding: With end-to-end speech coding (no transcoding) the speech quality scores are above MOS 3. Transcoded EVRC-HR - AMR515 PoC sessions will have a very low quality MOS around 2 The quality level may be unacceptable for end users Mean Opinion Score (MOS) results for a few narrowband speech samples Direct AMR 5.15 EVRC -HR AMR -> EVRC It is clear that users will notice the QoS difference between End-to-End and transcoded connections EVRC-> AMR It may be that transcoded speech is not considered as a proper PoC service 4,0 3,4 3,0 2,2 1,8 7 NOKIA

8 AMR in CDMA PoC?: Feasibility Point of View Example AMR usage for PoC in GPRS: AMR 5,15mode, 8 frames encapsulated in one AMR RTP payload according to RFC How this fits to CDMA? AMR 5.15 frames, 160 ms of speech, 103 octets H ToC AMR payload = 8 x 20 ms = 824 bits = 103 octets AMR RTP Payload packet, 110 octets RTP H ToC AMR payload RTP packet, 122 octets UDP RTP HToC AMR payload UDP packet, 130 octets IPv4 UDP RTP HToC AMR payload IP packet, 150 octets PPP IPv4 UDP RTP H ToC AMR payload PPP, 155 octets CDMA Case: Service option 33, without header compression. Fundamental RateSet -I channel. 8 NOKIA Up to 160 octets -Usage of basic ROHC header compression would improve the capacity and reduce delay variation No issues in using AMR for PoC even in current 1X SO 33 over RS I channel

9 Summary PoC requires wide interoperability for its success Carrier specific PoC systems with advanced features don't add value OMA PoC specifications to be available by end of year 2004 OMA PoC specifications are as compatible for CDMA as for GSM/GPRS With OMA PoC a carrier has widest selection of handsets and PoC servers OMA compliance ensures the future proofness of the solution The application level issues (both media and signalling) should be kept decoupled from the underlying radios Maximum flexibility for service evolution No special CDMA transport solutions should be tailored for PoC Generic packet channel based transport will greatly increase PoC capacity An end-to-end media codec should be used when possible Transcoder based solution could produce non acceptable speech quality There is no technical reason why AMR could not be used also in CDMA PoC PoC SIP signalling includes dynamic codec negotiation CDMA packet transport (1X SO33, 1xEV-DO, 1xEV-DV) is suitable for any codec No need to hard code specific PoC media codecs to 3GPP or 3GPP2 9 NOKIA