Maximum residual energy routing with reverse energy cost

The maximum residual energy path (MREP) routing has been shown an effective routing scheme for energy conservation in a battery wireless network. Past studies on MREP are based on the assumption that the transmitting node consumes power, but the receiving node does not. This assumption is false if acknowledgement is required, or if the ad hoc network has deployed the energy-conservation mode (sleeping mode). When backward energy consumption is present in transmission (i.e. the receiving end consumes energy), finding an MRE path that has enough energy for finishing the transmission has become NP-hard. We show in this paper a Dijkstra-like heuristic algorithm for finding the optimal MRE path. The new algorithm guarantees that once a path is found, it will have enough energy to finish the transmission task, while the original MREP algorithm, ignoring the backward energy costs, cannot guarantee that. We also show another routing technique that can extend the system life. The technique works for both MREP-based routing schemes.