An Efficient Multicast Routing Protocol in Multi-rate Wireless Ad Hoc Networks

In wireless ad hoc networks, many multicast routing protocols are proposed such as ODMRP, MAODV, etc. In general, the IEEE 802.11 standard is assumed as a MAC protocol in those protocol and multicast data packets are transmitted at the basic transmission rate which is 2Mbps at the IEEE 802.11 or 802.11b. However, if the multicast packet can be transmitted at higher transmission rates than 2Mbps in a multi-rate WLAN such as IEEE 802.11b, we can achieve higher throughput gain and lower transmission delay than those at 2Mbps transmission rate. In this paper, we propose a new multicast routing protocol in multi-rate wireless ad hoc networks. In the proposed protocol, we design a multicast mesh creation method considering multiple transmission rates between any two nodes in the ad hoc networks. We also design a multicast mesh maintenance scheme when the transmission rate between two nodes comprising a multicast mesh is changed because of node mobility. The performance of the proposed protocol is compared with ODMRP using ns2 simulation, and the proposed protocol shows higher packet delivery ratio and lower end-to-end delay than the ODMRP.