Energy Efficiency Maximization by Jointly Optimizing the Positions and Serving Range of Relay Stations in Cellular Networks

The new generation of wireless communication systems demands high system capacity and energy efficiency. As an important candidate technology, fixed relays are able to improve the system capacity and energy efficiency. In this paper, considering uplink data transmission in a single cell, we address the problem of joint optimization of the Positions of Relay stations (PR) and the serving Range of Relay stations (RR) for maximum energy efficiency. A novel uplink energy efficiency $(uEE)$ metric is defined for wireless cellular networks. The $uEE$ for both nonrelay and relay networks with uniformly distributed users is deduced. Through analysis and simulations, we investigate the influence of the network parameters, particularly PR and RR, on $uEE$ . The evaluation results show that we can maximize $uEE$ by the joint optimization of PR and RR. Finally, we comprehensively evaluate the effect of different network parameters such as cell radius, number of relays, ratio of resource allocation, and number of users on the optimal values of PR and RR for maximizing $uEE$ .