Proposal of autonomous transmission timing control scheme for collision avoidance in ad hoc multicasting

In this paper, we propose an autonomous transmission timing control scheme for collision avoidance in ad hoc multicasting. In ad hoc multicasting, packet collisions due to hidden node problems at upstream nodes cause packet losses at all downstream nodes. Therefore, collision avoidance mechanisms are important to improve packet delivery ratio at destination nodes. In this paper, we extend an On-Demand Multicast Routing Protocol (ODMRP) as a base multicast routing protocol to implement transmission timing control mechanisms. In the proposed protocol, each node constructs a neighbor-node list, and informs the neighbor node list to its own upstream node. As a result, upstream nodes can detect their hidden nodes by using these neighbor-node lists from their downstream nodes. Then, each node can select different transmission timing autonomously not to conflict the transmission timing. From the simulation results, it is shown that the proposed method can achieve high data delivery ratio by reducing packet corruptions.