Least-hop routing analysis of on-demand routing protocols

Wireless ad hoc networks are sensitive to energy consumption because the network nodes are battery operated. So far in practical ad hoc networks such as IEEE 802.11, there is no power control. This implies that to find a least-hop route from source to destination results in most energy efficient performance. In this paper, we analyze the route establishment procedure of the reactive routing protocols. When the route request packet RREQ propagates from source to destination, it suffers processing delay and potential congestion delay at each hop. Due to possible congestion, the RREQ packet first received by the destination does not necessarily correspond to the minimum hop route. The expected propagation delay along one path is discussed and we assert that it is proportional to the hop count of the path and the packet congestion probability p in term of p/(1-p). Then numerical analysis is given for the probability that the least-hop path is selected. Later we deploy two methods to improve the least-hop routing probability. The simulation shows the possibility that a least-hop route to be selected is increase.