Mobile multimedia supports with hierarchical multicast SIP framework on heterogeneous wireless networks

For supporting the mobile host (MH) to be the multicast receivers on wireless networks, the traditional approaches such as the Hierarchical Remote Subscription (HRS) and Bi-directional Tunneling with Mobile Multicast (BT-MoM) 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 multicast tree, which results in serious playback interruption and quality of service (QoS) degradation for the ongoing multimedia service especially when the MH are scattered over different kinds of wireless networks. In this paper, we propose a cross-layer framework and the Hierarchical Multicast Session Initiation Protocol (HMSIP), which extend the IETF Session Initiation Protocol (SIP) with the concept of multicast SIP session and integrate the underlying IP Multicast QoS routing protocol and the RSVP resource reservation technique, to support mobile multimedia multicasts. This framework significantly reduces handoff delays and deployment costs and hence achieves end-to-end QoS support for MHs on heterogeneous wireless networks. Further, we mathematically analyze handoff delays of the HRS, BT-MOM and HMSIP schemes. Moreover, simulation results show that the HMSIP can significantly achieve much more stable and lower handoff delays than those of the BT-MOM and HRS only with a small proportion of extra bandwidth than the bandwidth-optimal HRS, thereby supporting higher numbers of handoffs without interrupting multimedia playback of the mobile multicast activity. Tradeoffs between costs for deploying HMSIP Proxies in the framework and corresponding performances of the HMSIP families are discussed. Finally, multimedia QoS improvements of MHs are shown to emphasize advantages by integrating RSVP in this HMSIP framework.