Multi-criteria cooperative energy-aware routing in wireless ad-hoc networks

The cooperation among mobile hosts in wireless ad-hoc networks is usually in the form of nodes acting as intermediate relays that forward data from a source to an otherwise distant destination using point-to-point or point-to-multipoint links. A technique that has gained considerable recent attention is cooperative diversity, where nodes are organized for transmitting the same signal to a given, often otherwise unreachable, node. The receiver combines the multiple receptions to reconstruct the original signal. In this work, we examine the routing and power allocation problem under such a cooperative communications model, so as to obtain a cross-layer design of the network and the physical layer. We present and evaluate a multi-criteria cooperative routing algorithm that uses as parameters the nodes' residual energy and their transmission power. This algorithm selects for each source-destination pair a path, in the form of a sequence of groups of cooperative nodes, and the nodes' transmission powers. We perform a number of simulation experiments, assuming nodes with variable or fixed transmission power, evaluating the benefits of the proposed multi-criteria cooperative routing algorithm. The results show that our algorithm achieves significant energy savings and a larger number of successfully delivered packets than in the case where cooperation is not applied.