Energy-Efficient Cooperative Communications with Shared Relay in Wireless Networks

Cooperative communication (CC) is shown to be a promising technology to improve the spatial diversity without additional equipments and antennas. The choice of relay nodes can significantly affect the performance of wireless cooperative networks, e.g. energy- efficiency. Most of existing works focused on dedicating one relay node to a transmission pair in the network. However, the energy-efficiency can be improved by sharing each relay node among more than one transmission pair. In this paper, we first introduce the feasibility of shared relay assignment to improve the energy-efficiency while achieving the required bandwidth for each transmission pair. Then, the Minimum Energy Consumption (MEC) problem of CC with shared relay is defined, and we formulate it as a mixed integer optimization program and prove it is NP-hard. A Simulated Annealing (SA) algorithm is designed to solve this problem. We conduct abundant simulation experiments to evaluate the performance of our proposed algorithm. The simulation results show that the SA algorithm can save about 15 energy consumption on average than the previous work in wireless networks.