Energy-efficient precoding matrix design for relay-aided multiuser downlink networks

This paper considers the energy-efficient precoding matrix design for relay-aided multiuser downlink multiple-input single-output wireless systems. The precoders of the base station (BS) and the relay station (RS) are designed to maximize the transmit energy efficiency, defined as the ratio between the system sum rate and the total power consumption, under the quality-of-service constraints of the users and the transmit power constraints on the BS and the RS. In view of the fact that this precoder design problem is a nonconvex fractional programming, a successive Dinkelbach and convex approximation (SDCA) algorithm is proposed to handle this problem. Simulation results are provided to demonstrate the effectiveness of the proposed SDCA algorithm, and significant EE improvement as the number of antennas at the BS and the RS increases.