Study And Implementation Of Key Technology In Media Gateway

Computers have been universal for a long time, meanwhile, multimedia communication clients such as intelligent phones are developing at a high speed. It is a new time for telecommunication industry in China that the license of 3G (3rd Generation) being authorized. The normal function of telecommunication services such as voice phone call and short text message can't meet custmor's request any more. Hence, it is necessary to think over study and developing more value-added services. Both communication between PC (Personal Computer) clients and phones and video ring tones are great examples. Due to the high bandwidth of 3G network, the distinction between conventional Internet and telecommunication network is blurred. Hence, there are many services which are designed for Internet originally can be applied in telecommunication network now.Compared to normal text, multimedia is much more vivid and derect. In addition, now there is sufficient bandwidth. Thus, both the general voice call services and new value-added services have something to do with media. In China, with the developmet of NGN (Next Generation Networ), the construction of IMS (IP Multimeda Subsystem) for telecommunication operators is in progress. As a core network, it is really a problem to solve that how to realize intercommunication between various accessed network. This is also key techniques in media gateway. Based on NCSP (Next Core Service Platfrom) of EB (East telecommunication BUPT company), we introduce a material method of designation and realization of the key technology.The structure of this paper is as follows:Chapter 1 is introduction. It explains the concept and evolution history of NGN. In addition to characteristics and virtues of IMS core network, the compositon and functions of network elements which are related to media gateway are also introduceed. In the end, we have a simple explaination of SDP (Session Initial Protocol).Chapter 2 is an introduction of NCSP, including functions, structure and logic entities. Especially, there is interpretation for media server and application server.Chapter 3 is one of the main parts. In this chapter, we introduce the capacities of audio, video and media transfer in media server. Then we explain the concrete module designation, class realization and procedure realization combined to examples.Chapter 4 is another main part. The topic of this chapter is signal transfer. At first, BICC (Bearer Independent Call Control) protocol is introduced which is transferd to SIP (Session Initiation Protocol) wich each other. Second, it explains how to design the modules and process procedures. At last, this paper illustrates the realization of class and logic control.Chapter 5 is about the test stuff. We introduce the test conditions and envirements. The detailed function test items are listed in appendix. Then a conclusion is made by analyzed the data of performance test.Chapter 6, the last part is a summary. It introduces the current progress of the project. Besides, it lists some aspects of this project, which can be improved.