Research And Implementation Of IMS-based IPTV Media Server

With the rapid development of IPTV service and the expansion of the customer's number, whether IPTV as an important value-added service in telecommunication can be integrated into NGN has comes into people's eye. IP Multimedia Subsystem (IMS) is a general architecture used to build a unified platform for multimedia services, which is also one of NGN subsystems. Not only common functional entities of NGN and IMS can be reused in IMS-based IPTV but also with the advantage of unified session and user management, which is a new and hot research direction.In IMS-based IPTV, there are several key network entities including application server, media server, user equipment, Core IMS etc. In addition to traditional key technologies, such as media coding, transmission, distribution and storing technologies, there is a special demands which is the playing and control mechanism based on SIP session. Basing on the study of the functional entities and the key technologies and referring to the technical drafts of IMS-based IPTV which specified by the ETSI TISPAN, we compare the IMS-based IPTV architecture and technologies with the traditional IPTV. Based on the analysis of typical service process and the function requirements of media server, not only the functional modules and layered software architecture of media server in IMS-based IPTV have been designed, but also the media control and transmission channel negotiation and the mechanism of quality of service assurance can be provided. The architecture integrates the media control and distribution functions implementing streaming control with RTSP protocol and real-time transmission wrapped in RTP packages. Meanwhile, taking the typical service including BC, CoD, N-PVR and etc as the example, the realization of the functional modules has discusses and service state machines have been designed. We also adopt multi-thread technology to achieve the multi-user concurrency process.Finally, the prototype of media server has been verified in the laboratory network environment. The results shows that the prototype system can be satisfied with the IMS-based IPTV typical services demonstrations, meeting the basic need of media server according to ETSI TISPAN standards; the system scalability also is well.