Design And Implementation Of Center Control Server For Multimedia Trunking Communication System

The digital age of trunking communication has come, and digital trunking communication displays the traits of broadband and multimedia. Along with the trend, BWMTCS (Broadband Wireless Multimedia Trunking Communication System) arises at the historic moment, which is the inevitable outcome of the development of digital trunking communication. BWMTCS aims at achieving command and scheduling functions in specific applications. In this paper, we will achieve the CS (Center Control Server), which is the core of BWMTCS and serves requests of the terminal users to control call. Therefore, its implement is the key of the trunking system.So we firstly introduce the service control system of BWMTCS and its related network elements: Center Control Server,Registration Data Server, the R2interface which provides interaction between CS and RDS,the Dl interface which provides interaction between CS and DC (Dispatching Center) and the Ta interface which provides interaction between CS and RAN (Radio Access Network). At the same time, these are also introduced that Diameter protocol and open protocol stack OpenDiameter which are involved R2interface supporting authentication and authorization, as well as SIP and open protocol stack reSIProcate which are involved Dl/Ta interface.Secondly, the paper deeply researchs into the scheduling protocol of Broadband Wireless Multimedia Trunking Communication Control System, and expounds on register/unregister、 single cal、 group call、 dynamic regrouping and other service signaling processes.Thirdly, we design and realize the CS of BWMTCS.There are two kinds of SIP server architecture based on session model:Proxy and B2BUA (Back to Back User Agent).Proxy mainly provides routing service. Namely, it ensures that request message will be sent to place that is closest to target user. Proxy just keeps the state during SIP interaction instead of the state during call process, which causes that the Proxy is limited to be used to realize group call and other service signaling processes. As a result, the paper uses the B2BUA architecture to achieve the CS,which is stateful call control server and keeps the state during the whole process of call.At last, we test the CS based on B2BUA, the tested signaling processes includes register/unregister、 single cal、 group cal、 the speaking right and dynamic regrouping. The test results show that the signaling processes is correct, What’s more, the achieving CS has superior performance, which has a large service call signaling load-bearing capacity to carry on the request of terminal users.