The Design And Implemention Of Presence Server Based On IMS

The 3GPP (the Third Generation Partner Plan) has introduced the concept of IMS (IP Multimedia Subsystem) in the Release 5 of its 3G Specifications. The IMS domain has provided an end-to-end general multimedia service platform for the real-time and the non-real-time business users. Presence is an IMS service which provides functions to allow users to publish their status information, and subscribe others', as well as receive notifications while information changes. This paper focuses on the solution to design and implementation of the Presence Server based on IMS.In the first part, the paper introduces the system architecture of IP Multimedia Subsystem. And then it analyses the Application Server and Presence Service in IMS. Based on these issues, the requirement of Presence Server in IMS is put forward.In the second part, research and analysis are conducted from the perspectives of Presence service model, the definition of service, related protocols and service application scenarios. And then the paper presents a module architecture and discusses key design issues for each module. Special attention is paid on such detail designs as service logic processing,SIP message processing, subscription state machine and service data model, etc. Session Serialization and Data Partitioning techniques is proposed to solve performance problem of Presence Server at a large volume users.In the third part, the procedure for implementation and test of Presence Server is described. The result proves that the solution to design and implementation of Presence Server fulfils the demands of devices and servers in the network. And the prototype of Presence Server provides a reference for industry product.The final part makes a brief summary of the research work and discusses the improvable areas of the implementation, which will be the future work of the paper.