Multipath Routing in Ad Hoc Wireless Networks with Omni Directional and Directional Antenna: A Comparative Study

Several routing schemes have been proposed in the context of mobile ad hoc network. Some of them use multiple paths simultaneously by splitting the information among multitude of paths, as it may help to reduce end-to-end delay and perform load balancing. Multipath routing also diminishes the effects of unreliable wireless links in the constantly changing topology of ad hoc networks to a large extent. Route coupling, caused by the interference during the simultaneous communication through multiple paths between a pair of source and destination, severely limits the performance gained by multipath routing. Using node disjoint multiple paths to avoid coupling is not at all sufficient to improve the routing performance in this context. Route coupling may be reduced to a great extent if zone disjoint or even partially zone disjoint paths are used for data communication. Two paths are said to be zone disjoint if data communication through one path does not interfere with other paths. Large path length (number of hops) also contributes to the performance degradation resulting in high end to end delay. So zone disjoint shortest multipath is the best choice under high traffic condition. However, it is difficult to get zone disjoint or even partially zone disjoint multiple routes using omni-directional antenna. This difficulty may be overcome if directional antenna is used with each mobile node. In this paper, we have done a comparative study on the performance of multipath routing using omni-directional and directional antenna. The result of the simulation study clearly shows that directional antenna improves the performance of multipath routing significantly as compared to that with omnidirectional antenna.