Energy Efficient Clustering and Beamforming for Cloud Radio Access Networks

摘要

Cloud radio access network (Cloud-RAN) is recognized as one of the key enabling techniques for 5G due to its advantages in flexibility. In addition, the greatly increased energy efficiency (EE, evaluated by bits/Hz/J) is listed as one main objective when designing 5G wireless network. In this paper, we concentrate on EE optimization through Cloud-RAN enabled flexible multicell cooperative transmission. A joint clustering and beamforming problem for EE optimization is formulated. Due to the combinatorial nature of the clustering process and the non-convexity of the energy efficient beamforming design, the problem is difficult to solve directly. Therefore, we propose a hierarchical iterative framework to solve the problem. The origin optimization problem is decoupled into two subproblems, i.e., energy efficient beamforming problem and energy efficient cluster forming problem. Coalition formation game theory and fractional programming are utilized to obtain the optimal network cluster partition and beamformers respectively. Simulation results demonstrate the superior performance of the proposed algorithms.