Optimal energy-efficient power allocation for multiuser relay networks

The rapid growth of diversified applications has led to significant increase in data traffic and energy consumption in wireless networks. Hence, the energy efficiency becomes one of critical performance indices for designing next-generation wireless networks. In this paper, an optimization framework of power allocation is investigated for maximizing energy efficiency in multiuser relay networks. Under a total power constraint, we formulate the design problem with the objective as the ratio of the spectral efficiency over the entire power consumption of the network. An optimal energy-efficient power allocation algorithm is proposed for the source and the relay nodes to approach the maximum efficiency in an iterative manner. Compared with a heuristic scheme where the total available power is equally allocated to all nodes, the proposed optimal power allocation algorithm can dramatically improve energy efficiency with a slight loss in spectral efficiency.