Synchronized multimedia multicast on mobile IP networks

With the IP multicast technique, the source sender can efficiently transmit only one copy of the multimedia stream to multiple mobile hosts simultaneously. However, because the mobile host can roam to any wireless cell, the multimedia stream issued by the same source may follow different paths to different mobile hosts, which introduces different end-to-end delays. As soon as the mobile host handoffs to another wireless cell with a different end-to-end delay, it will not receive the correct streaming multimedia data for continuous playback. In this paper, we propose the synchronised multimedia multicast (SMM) scheme to achieve the two most important characteristics that the traditional home subscription (HS) and remote subscription (RS) schemes cannot support. First, SMM scheme supports synchronized multimedia multicast on mobile IP networks and achieves seamless playback of continuous media stream when the mobile host handoffs. Further, combined with the fine granularity scalability (FGS) approach in the MPEG-4 standard, the SMM scheme achieves unlimited numbers of handoff only at the cost of degraded video quality for a short period after handoff.