Research On Terminal Mobility Management Based On Mobile SIP

Next-generation Wireless Networks(NGWN) are expected to be composed of various heterogeneous wireless access networks and capable of providing"Always Best Connected(ABC)"services to mobile terminals equipped with multiple radio interfaces .To meet this goal, one of the most important issues is how to support seamless roaming of users across heterogeneous wireless networks.So far, numerous mobility management solutions operating in different layers have been proposed by the international standardization organizations, such as the Mobile Internet Protocol(Mobile IP) in the network layer, the mobile Stream Control Transmission Protocol (mSCTP) in the transport layer and the Session Initiation Protocol(SIP) in the application layer. Among these solutions, SIP is considered as an attractive candidate to support mobility in NGWN due to its excellent extensibility, sclability and achievement of true end-to-end mobility management. Besides, SIP is also accepted as the signaling protocol used for session control in the IP Multimedia Subsystem(IMS) by 3GPP. Although SIP is an important application-level mobility management protocol used for supporting seamless mobility, the handoff mechanism in the traditional SIP mobility architecture suffers from undesirable delay and packet loss, which is unacceptable to delay-sensitive applications of IP multimedia such as Voice over IP(VoIP) and streaming video with stringent Quality of Service(QoS) requirements. In this thesis, an improved SIP mobility architecture based on Anchor Mobility Proxy(AMP) that supports fast soft handoff is proposed to alleviate the transmission delay of the SIP mobility signaling messages and reduce the packet loss, hence improve the handoff performance. Moreover, the SIP-AMP solution provides a set of whole location management and handoff management schemes for multi-mode mobile terminals through the modeling of the anchor field mobility management in the heterogeneous environment.To achieve fast deployment of SIP-AMP architecture in the Next Generation Networks(NGN), a Session Border Controller(SBC) based implement solution is concerned in this thesis too. Meanwhile an experiment system based on SBC and SIP test soft terminal named ePhone ,developed by CSSC lab of HUST both , is established in the lab environment to emulate vertical handoff procedure of the subnet mobility.And the test result shows that the SIP-AMP based mobility management solution gained better handoff performance than the traditional Mobile SIP solution in most cases especially in the long distance communication scenario.