Energy aware unicast geographic routing

In this paper, we are investigating the optimal radio range minimizing the energy globally consummed by a geographical routing process. Considering a geographical greedy routing protocol and a uniform distribution of nodes in the network area, we analytically evaluate the energy cost of a multi-hop communication. This cost evaluation corresponds to the asymptotic behavior of the routing protocol and turns out to be very accurate compared to the results obtained by simulations. We show that this cost is function of the node intensity and we use this result to deduce the optimal radio range. We evaluate this range with two energy consumption models, the first one considering the energy consumed by transmission operations only and the second one considering both transmission and reception operations. These results can be used in two ways. First, the nodes range can be tuned in advance as a function of the expected node intensity during an off-line planning. Second, we propose an adaptative algorithm where nodes tune their powers according to an on-line evaluation of the local node intensity.