Design And Implementation Of The Interworking Gateway Between WebRTC System And IMS

WebRTC (Web Real-Time Communications) is a kind of real-time communication technology through audio and video, which is independent on the third-party plugins and natively supported by the brower. The different type of browsers on different operating systems can communicate with each other if they follow the same WebRTC standard. The emergency of WebRTC technology has an impact on the multimedia real-time communication services used by the traditional operators in IMS networks, major operators and equipment manufacturers are striving to combine WebRTC technology with IMS services to seek new development direction for traditional multimedia services.This paper studies the signaling and media interworking between WebRTC system and IMS system, and proposes a kind of realization scheme of interworking gateway. First of all, based on the research of WebRTC and IMS related protocol specification, the paper analyzes the function and position of the interworking gateway in WebRTC system, and focuses on how to realize the peer-to-peer audio and video communication between WebRTC and IMS terminals by the design on the level of signal and media. On the one hand, the gateway needs to support converting ROAP signal in the WebRTC system to SIP signal used in IMS system. On the other hand, it should have the function of media session negotiation and coding conversion. Based on this research, the paper introduces related call service flow and the module function partition of interworking gateway, designs the state machine of the call module and determines the realization scheme of the gateway. The interworking gateway can be divided into signal gateway and media server. The signal gateway is responsible for the signal session negotiation and the media server is in charge of building a media P2P direct connection with the communication parties and the relaying and forwarding of the media stream. At last, the function and performance tests of the scheme are carried out to verify the reliability and usability of the system.