Joint power allocation and relay selection in cooperative ad-hoc networks with multi-hop diversity

We are concerned with the transmit power optimization in a multi-hop wireless relay network with multi-hop diversity. With the multi-hop diversity in such a network, we propose a joint near optimal power allocation and routing protocol, namely, power-optimized multi-hop cooperative transmission protocol (POMC) to minimize the total power consumption which guarantees the certain outage probability in the system. POMC is based on the linear combination of copies of the same massage by two previous hops along the route in order to exploit the multi-hop diversity advantages. The relay selection and power assignment strategy for conventional linear combining schemes, i.e., maximal ratio combining, equal gain combining, and selection combining at the receiver are analytically derived. Simulation results reveal that exploiting the multi-hop diversity, enhances the performance of the multi-hop wireless networks. We show that the POMC, depending on the type of the linear combining scheme, can achieve the power efficiency between the 64.8% and 73.7% in both the random and the linear network models compared to the existing ad hoc routing algorithms, where the cooperative routes are constructed based on the selection of the relay with highest received SNR at each hop.