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Analysis of Ip Multimedia Subsystem for 3G Networks MEE10:08 ANALYSIS OF IP MULTIMEDIA SUBSYSTEM FOR 3G NETWORKS BY Mohammad Rezaul Hossain Morshed Md. Humayun Kabir A Thesis Presented in partial fulfillment of the requirements for the degree of Master of Science in Electrical Engineering with specialization in Telecommunication Blekinge Institute of Technology December 2009 Blekinge Institute of Technology School of Engineering Department of Telecommunication Systems Supervisor: Alexandru Popescu Thesis Abstract 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. i Acknowledgement We would like to express our immerse gratitude to our supervisor Alexandru Popescu for his guidance and encouragement towards the completion of our thesis work. We would also like to thank our parents for their support and prayers and our friends who have contributed one way or the other to the success of this work. God bless you all. ii Table of Contents Thesis Abstract ............................................................................................................................ i Acknowledgement ...................................................................................................................... ii List of Figures .............................................................................................................................. v Chapter 1 ................................................................................................................................... 1 1.1 Background ...................................................................................................................... 1 1.2 Overview of IMS .............................................................................................................. 2 1.3 Motivation for the use of IMS ......................................................................................... 2 1.4 Protocols used in IMS ...................................................................................................... 3 1.5 QoS support in IMS .......................................................................................................... 5 1.6 Thesis Motivation ............................................................................................................ 6 1.7 Thesis Out line ................................................................................................................. 7 Chapter 2 ................................................................................................................................... 8 2.1Introduction ...................................................................................................................... 8 2.2 IMS Architecture Design .................................................................................................. 8 2.3 IMS and SIP .................................................................................................................... 13 2.4 SIP and Quality of Service .............................................................................................. 18 Chapter 3 ................................................................................................................................. 19 3.1 Introduction ................................................................................................................... 19 3.2 The Couple Model ......................................................................................................... 23 3.3 The Associated Model using one policy server ............................................................. 25 3.4 The Associated Model using two policy server ............................................................. 26 3.5 The Non‐Associated Model ........................................................................................... 28 3.6 Conclusions .................................................................................................................... 29 Chapter 4 ................................................................................................................................. 30 4.1 Introduction ................................................................................................................... 30 4.2 SIP presence architecture .............................................................................................. 32 iii 4.3 Analysis of presence server traffic load ......................................................................... 33 4.4 Mathematical Analysis .................................................................................................. 34 Chapter 5 ................................................................................................................................. 40 5.1 Introduction ................................................................................................................... 40 5.2 Proposed Access priority Model .................................................................................... 41 5.3 Proposed Timer ............................................................................................................. 42 5.4 Proposed Model to Optimize Simultenious Sessions .................................................... 44 Chapter 6 ................................................................................................................................. 48 References: .............................................................................................................................. 50 iv List of Figures Figure1. 1: COPS Principle ......................................................................................................... 4 Figure ‐2. 1: IMS Architecture Overview ................................................................................... 9 Figure ‐2. 2: SIP session setup example with SIP trapezoid .................................................... 15 Figure 3.1: Generic media authorization network model. ...................................................... 21 Figure 3. 2: The couple model ................................................................................................ 23 Figure 3. 3: The Associate model using one policy server. ...................................................... 26 Figure 3. 4: The Associated Model using Two Policy Servers .................................................. 27 Figure 3. 5: The Non‐Associated Model ................................................................................. 28 Figure 4. 1: SIP presence service message flow ...................................................................... 31 Figure 4. 2: SIP presence architecture ..................................................................................... 32 Figure 4. 3: Publish and Notify Queues in a PS. ....................................................................... 35 Figure 4. 4: State Transition Graph for Queue System with Batch Arrival and Controlled Vacation. .................................................................................................................................. 38 Figure 5. 1: Example of PoC 1 to many Group session (voice transmission)[5‐4] ................... 40 Figure 5. 2: Markov model for accessing session .................................................................... 42 Figure 5. 3: Markov model for PoC server states .................................................................... 44 Figure 5. 4: session states of a PoC Client ............................................................................... 46 v Chapter 1 Introduction IP Multimedia subsystem is a set of arrangements that explains the Next Generation Networking (NGN) architecture for executing IP based telephony and multimedia services. IMS describes a complete architecture and framework that facilitates the convergence of video, voice, data and mobile network technology over an IP‐based infrastructure. IMS remove the gap between two most successful communication models that is cellular and Internet technology. There was a time we can’t even imagine to play an online game or join a videoconference from anywhere using 3G handheld devices. This is the main vision of IMS to provide all service in cellular that the Internet provides. [1‐1] 1.1 Background IP Multimedia subsystem
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