Research And Implementation Of SIP-Based Mobility Management

In recent years, with the development of mobile communication technology and the rapid popularization of Internet, mobile multimedia services are more and more favored by users. Mobility management theory is the basis of supporting the needs of mobile users. Mobility management involves various management planes and all levels of network protocol, which has been widespread concerned by numerous research organizations. On the other hand, Session Initiation Protocol (SIP) as the multimedia session control protocol of the next-generation IP Multimedia Subsystem, has proven to be one of suitable techniques in mobility support capabilities. Therefore, this paper makes in-depth research of SIP-based mobility management.This paper reviews the basic concepts and principles in mobility management, and the related handoff management and location management is also introduced. Then, this paper has outlined the representatives of various levels of network protocols, and the network layer mobility management techniques-Mobile IP is investigated in detail. Subsequently, the syntax of SIP protocol, the entity, and the interaction conversation procedure between them are discussed in detail. After that, the existing mobile SIP protocols are reviewed, where the impact of protocol performance, such as handoff delay, packet loss rate, etc, is discussed.This paper firstly proposes a SIP-based mobile soft handoff method-BSIP. Through the extension of SIP message, it realizes the bicast mechanism and achieves an end-to-end mobile soft handoff method. It details the protocol application scenario, the message content and the handoff control process. Analysis is shown that by the use of this protocol handoff latency and packet loss rate significantly are to be reduced but with the increased communication range, the cost of signaling of handoff control and the consumption of bicast data are also increased, bringing too much traffic overload on the network. In addition, other problems in the protocol have also been described, such as the bicast synchronization problem.In order to solve the problems of BSIP, aiming to further optimize the protocol performance, and an improved version of BSIP, named hierarchical BSIP (HBSIP) was put forward. A hierarchical structure is used in HBSIP, which is able to balance between the protocol performance and the protocol cost. While maintaining the original handoff performance, HBSIP is able to considerably reduce the loads on the network. The paper introduces the application scenario, the message interaction flow and the overall handoff control process. It is shown that HBSIP behaves a good switching performance, and also avoids control information and data stream spreading out of the domain when the mobile terminal is moving cross in the domain.Finally, analysis and simulation are made for evaluating the proposed protocols in this paper. By introducing an evaluating model, the proposed BSIP, HBSIP are analyzed in terms of signaling cost and data consumption, compared with the traditional mobile SIP. It is shown that, as a result of adopting a more complex handoff control, BSIP will produce a larger signaling load. Due to the use of the hierarchical mechanism, HBSIP solves the problem well. On the other hand, the proposed protocols are evaluated by simulation in NS2. Compared to traditional mobile SIP protocol, HBSIP protocol has the smaller handoff latency and packet loss rate, achieving a seamless handoff, is one of candidate techniques for future mobile communication systems.