A cooperative multicast routing protocol for mobile ad hoc networks

Many multicast routing protocols and algorithms have been proposed to support different group-oriented applications in mobile ad hoc networks. However, the conventional tree-based and mesh-based multicast routing protocols generally suffer from frequent link breakage and high communication overhead, respectively. In this paper, we propose a cooperative multicast routing protocol, COMRoute, that incurs low communication overhead while guaranteeing reliable network connectivity. COMRoute utilizes cross-layer design by physical-layer cooperative transmission, MAC-layer clustering, and network-layer multicast routing. Specifically, the physical-layer multi-node decode-and-forward cooperative transmission provides reliable transmission links. At MAC layer, nodes are classified into clusters. In each cluster, the cluster head, serving as a gateway, is responsible for inter-cluster transmission, while other nodes perform cooperative reception. Based on the clustered architecture, we design an on-demand source-based multicast routing protocol at network layer, which takes diversity into account for route establishment. Moreover, COMRoute implements a mechanism to mitigate the asymmetric cooperative transmission problem. Our simulation results show that COMRoute outperforms the representative multicast routing protocols in terms of traffic overhead, delivery ratio, and energy consumption.