Research Of Voice Communication Based On SIP

With the quick development of the communication technology, more and more technologies of communication are being used in our human lives, which has greatly affected our manner of communicating. These also affect the frame of telecom market. The development of voice communication is from just simple circuit switch networks to VoIP, until now the technology of NGN. As a result, the telecom operators can push new services with a lower cost even the combination of multimedia services rapidly. Therefore, the conversion from traditional telephone network to IP network becomes a general trend.This thesis analyses the development of voice communication according to the condition of voice communication technologies currently, and puts emphasis on an important signaling protocol in voice communication on IP network-the SIP protocol. As the 3GPP has assigned SIP as the signaling protocol in 3G IMS,the research on SIP becomes more important. We can use SIP to create, modify, and terminate a session easily, also realize the access of Softswitch under a lower cost.Based on the analysis of different protocols in Softswitch architecture, the thesis proposes an implement of access Softswitch in SCDMA with SIP protocol. SCDMA is a wireless standard system with domestic independent technology. Firstly, the system uses simple circuit switches. In the progress of evolution to IP network, we can use an access gateway system with SIP to realize the communication between wireless terminals of SCDMA and PSTN users using the standard Softswitch.The thesis summarizes the implements of SIP signal module of SCDMA access gateway system. The module acts as an SIP gateway which to be an agent for users registration and calling. The module also transforms the Q.931 from base station to SIP when it communicates with CC and MM. The thesis introduces important protocol flow and design method, also describes the key technologies and problems needed to be resolved in practice. At last, the network topology was designed to test the SIP module;the result shows that the SIP gateway function module has thefunctions that system need. This has also provided a rapid method to resolve the SIP access with Softswitch equipment, In the section of summary, the disadvantages of the thesis are presented, which form the objectives for the future research and works.