NOKIA VoLTE和eSRVCC原理.pptVIP

Company Confidential * ? 2010 NSN ATCA MSS MGW System Architecture / 2010-06-18 / HCK * ? 2015 NSN VoLTE Fundamental Wokshop / Fuzhou / 2015-01-01 VoLTE Fundamental Fuzhou, 2015-01-08 VoLTE Introduction What is VoLTE? LTE (Long term Evolution) aka 4G, is the wireless communications standard developed by 3GPP standardization, to offer high speed with low latency. LTE is packet-switched network only. LTE network architecture does not include the traditional 2G/3G voice services. Voice over LTE is the solution to provide the Voice service capability based on GSMA IR.92 specification. - Real time traffic - Quality of Service - Interoperability to existing CS voice network IP Multimedia Subsystem (IMS) enables integrated voice, data and multi-media services interworking between different access networks. IMS is based on SIP call control for creating, modifying, and terminating sessions. VoLTE Network Architecture Overview CSCF（Call Session Control Function）：多媒体呼叫会话过程中的信令控制 MGCF（Media Gateway Control Function）：执行IMS与CS域的互通；不同域间协议转换 MGW（Media Gateway）：连接不同域的用户面；不同网络之间的编解码转换 VoLTE Bearer Combination The VoIP service has specific bearer combination requirements： - QCI1 dedicated bearer for voice call. - QCI2 dedicated bearer for video call. - QCI5 dedicated bearer for SIP signalling to the IMS. - Default non-GBR bearer (QCI8-9) for data transfer (always-on). QCI Guarantee Priority Delay budget Loss rate Application 1 GBR 2 100 ms 1e-2 VoIP 2 GBR 4 150 ms 1e-3 Video call 3 GBR 5 300 ms 1e-6 Streaming 4 GBR 3 50 ms 1e-3 Real time gaming 5 Non-GBR 1 100 ms 1e-6 IMS signalling 6 Non-GBR 7 100 ms 1e-3 Interactive gaming 7 Non-GBR 6 300 ms 1e-6 TCP protocols:browsing, email, file download 8 Non-GBR 8 300 ms 1e-6 9 Non-GBR 9 300 ms 1e-6 VoLTE Signaling Overview SIP Protocol Stack - The Session Initiation Protocol (SIP) is an application-layer control (signaling) protocol for creating, modifying, and terminating sessions with one or more p