PRDS: A Priority Based Route Discovery Strategy for Mobile Ad Hoc Networks

Most reactive route discovery protocols in MANETs employ a random delay between rebroadcast route requests (RREQ) in order to avoid “broadcast storms”. However this can lead to problems such as “next hop racing”, and high redundancy in the rebroadcasting. In this paper we propose a Priority-based Route Discovery Strategy (PRDS) to address both problems. PRDS is a distributed algorithm that assigns a high rebroadcast priority to “good” candidates for the next hop to reduce next hop racing; it also introduces a competing procedure to keep “bad” candidates from rebroadcast to alleviate “rebroadcast redundancy”. PRDS is a general mechanism that can be applied to different reactive routing protocols to improve the routing performance by enhancing route quality while reducing routing overhead. As an example, a macrobian route discovery strategy using PRDS (PRDS-MR) is introduced and evaluated via various simulations. Simulation results show that PRDS-MR outperforms AODV in terms of packet delivery ratio and delay while decreasing routing overhead up to 50%~80%.