The Study of False Route Breakage in IEEE 802.11 based Ad Hoc Networks

In a 802.11 based mobile ad hoc network (MANET), the routing protocol may wrongly assume that a route is broken due to temporal packet loss in connectivity arising from multiple packet collisions, which we term as a false route breakage. In this paper, we investigate the impact of false route breakages in MANETs. It is found that false route breakage is dependent on the size of packets transmitted in a network and the path length of a source-destination pair. We present a protocol enhancement to the IEEE 802.11 MAC protocol which increases the reliability of wireless links by reducing false route breakages. We achieve the goal of alleviating false route breakages by initiating a HELLO message to the sender whenever the number of RTS received by a receiver exceeds a threshold. The simulation results show that the proposed modification substantially reduces the false route breakages and improves throughput by up to 35%