Energy-efficient mobile relay deployment scheme for cellular relay networks

In this paper, an efficient mobile relay deployment scheme to select the deployment sites for mobile relay stations (MRSs) from the candidate positions is proposed, aiming at maximizing energy efficiency (EE) while guaranteeing the spectral efficiency (SE) requirement and the coverage constraints of mobile users (MUs). Firstly, an interference graph construction method is proposed to calculate the interference at MUs served by MRSs. Then, the deployment scheme at each observation time is proposed and our framework consists of three main algorithms. The first algorithm based on the extended Hungarian deployment algorithm is proposed to find the optimal solution, i.e., minimum movement distance. In addition, a greedy deployment algorithm and a static deployment algorithm are proposed to compare with the extended Hungarian deployment algorithm. Furthermore, we compare the performance of these algorithms via simulations and analyze the impact of various parameters on the performance. Simulation results demonstrate that the extended Hungarian deployment algorithm can considerably improve system EE compared to the other two algorithms. Moreover, relay switching occurs more frequently and average relay service time reduces with the increase of maximum speed of MUs. (C) 2016 Elsevier B.V. All rights reserved.