Energy efficient radio range allocation in ad hoc wireless sensor networks

In ad hoc wireless sensor networks, energy use is in many cases the most important constraint since it corresponds directly to operational lifetime. The lifetimes can be extended by topology management schemes, such as GAF, Leach and SPAN that put the redundant nodes for routing to sleep in order to save the energy, and by optimizing each node's radio range as this determines the number of neighboring nodes that collaborate to forward data to a base station or sink. In this paper we modify the network simulation tool NS2 to accommodate nodes with different transmission ranges, and develop simulation and energy models of such topology management schemes for three simple linear wireless sensor networks. Our detailed packet-level simulations show that if the radio range is optimized then the network lifetime can be improved by 40% and 60% respectively compared with the best case where equal radio range and commercial off the shelf (COTS) systems are used.