Research Of Charging System On IMS

With the rapid development of IP network technology,mobile communication technology and the multimedia technology , people put forward more and new requires for future communications network,only voice communication can not meet the needs of users,however,the multimedia differentiated service combining voice,data,and video has become the urgent needs of the users.3GPP puts forward IMS(IP Multimedia Subsystem)which can support IP multimedia services subsystem. IMS is a hierarchical structure,the business layer,control layer and bearer layer are separated,and it focus on users'attributes and access-independent. IMS above structural features makes it possible to fix mobile convergence so as to provide a new form of a variety of multimedia services for users,it is considered to be the core technology of next generation networks. The introduction of IMS will bring a lot of new service,a variety of charging for the every service has become the most important attention of Operators. This article study the current charging system of the IMS in order to design a practical and feasible charging system.For charging problems of IMS. Firstly,this article introduces the concept, characteristics,standardization developing and a variety of service. Secondly,analyzes the IMS architecture,including some important functional entities and reference points function,takes focus on the architecture of SIP protocol and the Diameter protocol and analyzes the application in IMS. Then, a detailed analysis of charging processes,basic principles and charging rules of online charging and offline charging. On this basis and combining with the study of PCC architecture,presents a design programe based PCC architecture that is the charging moves to the network side. Then,for online charging,designs charging-related functions of Serving Call Session Control Function S-CSCF,including online charging architecture,CTF and so on,so as to achieve to process different charging detailed scene for S-CSCF,Finally,tests the system by the specific test cases and verifies the feasibility and correctness of this online charging system.