Research And Implementation Of IMS Based Video Conference System

Since 1960s, video conference has experienced the development of information technology from analog to digital signals, and that of network from the private to the public. However, it cannot provide high-quality video conference communications for the public because of the network technology and cost problem. In the recent years, IMS, proposed by 3GPP, aims to provide high-quality multimedia services in the IP network and gives the development of video conference new impetus.This paper designs an IMS-based video conference on the basis of the research on the structure and session control mechanism of IMS. It makes up the centralized model for the system with the function analyses. After that, it designs the architecture of the system, establishes an IMS network with the help of an open source tool (FOKUS) and develops the application.The AS uses the ISC interface to communicate with SIP client and Conferencing API&MSCML to control the media of a conference. Besides, it provides a graphical user interface for the conference operation.As to the realization of the conference server, this paper designs the session flow of the Ad-Hoc conference creating, Call-in and Call-Out conference joining, inviting users to join the conference, quitting from current conference, terminating the conference by the host, asking a client to quit from the conference, muting a conference client and so on. Then it uses SIP Servlet API to finish the development of the application and JSP&Struts to complete the graphical interface. The AS's identity in IMS is PSI, which is different from user identity held by the conference client. Therefore, there is a need to make up a mechanism to fulfill the special session control function for PSI. Filter matching rules successfully completes the PSI's request routing.This paper breaks the limitation that only PC client can access to the conference system for a SIP mobile phone can also get the conference service. At the same time, it provides technical support and experience for new business of 3G.