On mitigating the broadcast storm problem with directional antennas

Broadcast has been widely used in mobile ad hoc networks (MANETs) as a communication means to disseminate information to all reachable nodes. However, the conventional broadcast scheme that broadcast packets omnidirectionally suffers from several drawbacks: excessive amount of redundant traffic, exaggerated interference/contention between neighboring nodes, and limited coverage (as a result of contention/collision). This is termed as the broadcast storm problem in S.Y.Ni et al. [1999]. In this paper, we address this problem in MANETs with the use of directional antennas. We propose three schemes: on/off directional broadcast, relay-node-based directional broadcast and location-based directional broadcast, in the increasing order of implementation complexity. We implement the proposed schemes in qualnet and compare their performances against the conventional broadcast scheme. The simulation results indicate that the proposed schemes outperform the conventional omnidirectional scheme with respect to coverage, latency, and redundancy over a wide spectrum of network topology and node mobility.