MODIFIED CLUSTER BASED BROADCASTING IN AD HOC WIRELESS NETWORK

In an ad-hoc network, a packet is transmitted by a node is received by its neighbors. Redundant transmissions cause congestion, contention and collisions. The total numbers of transmissions (Forward Nodes) are used as cost criterion for broadcasting. The basic objective is to reduce broadcast redundancy by minimizing number of forward nodes without introducing excessive overhead and save scare resources such as energy and bandwidth. The problem of finding the minimum number of forward nodes is NP-complete. In this paper, cluster architecture of network is used. It chooses forward node set (consists of clusterheads and gateways) to relay the broadcast packet. Each clusterhead computes its forward node set that connects its adjacent clusterheads. A non-clusterhead node just relays the broadcast packet if it is selected as a forward node or else it does nothing. So broadcast operation is restricted only to clusterheads and nodes in locally selected forward node set. The information of clusterheads is piggybacked with broadcast packet to further reduce each forward node set. In simulation, effect of node transmitter range is checked on the performance of algorithms in the terms of average number of Forward Nodes, Broadcast Redundancy, and Broadcast Delivery Rate.