Maximizing network lifetime under a fixed energy budget in mobile ad hoc networks

Given a fixed energy budget for the operation of wireless ad hoc networks, we show that supplying it in quanta to the nodes over time, rather than all of it initially, can yield a significant improvement in the network lifetime, under the same traffic conditions and performance requirements. The network lifetime is defined as the time by which the first node runs out of energy. We refer to this strategy of resource allocation as "on-demand recharging". Until now, studies conducted for mobile ad hoc networks (MANETs) assume that the network nodes are initially fully charged with the available battery power and are not recharged thereafter. With the aid of extensive simulation studies conducted in ns-2 on standard routing protocols like CMMBCR, AODV, DSR and ABR, we show that given a fixed energy budget, on-demand recharging can improve the network lifetime by a factor of 1.5 to 3. The final protocol selection can be made taking into account the tradeoff between the feasibility of recharging and the application requirements.