On design of the hierarchical multicast SIP for multimedia fast handoff on 3G wireless networks

For supporting the Mobile Host (MH) in the wireless networks to be the multicast receivers, the traditional approaches such as the Remote Subscription (RS) and Bi-directional Tunneling (BT) integrate the Mobile IP protocol with the IP multicast technique. However, they inherit intrinsic problems to handle mobility and suffer significant delays to rebuild the multicast tree when the MH moves out of the tree, which results in serious playback interruption and quality of service (QoS) degradation for the ongoing multimedia service. To solve this problem, we propose the Hierarchical Multicast Session Initiation Protocol (HMSIP), which integrates the IETF Session Initiation Protocol (SIP) with the IP Multicast protocol and the RSVP resource reservation technique, to reduce the delay for rebuilding the multicast tree and support fast handoff for the MH with guaranteed multimedia QoS when the MH hands off to the neighboring cell. Further, we mathematically analyze handoff latencies to rebuild the multicast tree for the HRS, BT and HMSIP schemes. Finally, we prove the HMSIP can reduce the delay time occurred when the Mobile Host re-joins Multicast Tree.