AbstractsCommunication

The IP Multimedia Subsystem is seen as the promising solution for the next generation multimedia communication. The IP Multimedia Subsystem will make Internet technologies almost anywhere, anytime and on any device such as email, web, instant messaging, presence and videoconferencing. Presence is one of the most important basic services in IMS. It is the service that allows a user to be informed about the reachability, availability and willingness to communicate with other user. Push to talk over Cellular (PoC) is one more service in IMS that allows users to engage in immediate communication with one or more users. Instant Messaging (IM) is the service that allows a user to send some content to another user in near real time. In this thesis work, we have discussed overall IMS architecture and identity the major issues to improve the existing protocols in IMS for better system performance.Our work is centered on Presence service, Push to talk over Cellular, Instant Messaging and IMS session setup. In this thesis three possible session establishment scenarios in a mobile environment is compared by using an analytical model. The other problem areas in optimizing presence service, dimensioning a PoC service and analyzing service rate of IM relay extensions in IMS are identified.