Design and analysis of cooperative mobile multicast protocol (CMMP) for intermittent network connectivity

Multicast services have received great interests recently. They normally cannot tolerate high packet delay and high loss rate. However, multicast services may be disrupted in mobile and wireless networks. Disruption may be caused by different reasons. In this paper, we consider the disruption resulted from handoffs between base stations. Although many mobile multicast protocols have been proposed, they primarily consider the routing in mobile environment. The protocols usually do not consider how to reduce packet delay and packet loss rate caused by intermittent radio connectivity. In this paper, we propose a mobile multicast protocol which utilizes cooperative communications for intermittent connected networks. Specifically, multicast packets are cached in helpers, which in turn relay the packets to the mobile hosts disconnected from the network. Therefore, multicast services still can be delivered to the disconnected mobile hosts. Hence, packet loss rate can be reduced and throughput can be increased significantly. Most of the studies of cooperative communications focus on MAC and physical layers. We demonstrate how cooperative communications can benefit multicast at network layer. Both mathematical model and simulation are developed to analyze the performance of the proposed protocol.