Joint RRH Selection and Power Allocation forEnergy-Efficient C-RAN Systems

Abstract

This paper addresses the energy efficiency (EE) based Remote Radio Heads (RRHs) selection problem in cloud radio-access network. In specific, a low-complexity 2-stage iterative algorithm is developed for this purpose by jointly employing the coordinated multi-point (CoMP) and user-clustering techniques. The first stage of the algorithm comprises of two steps, the first step applies a greedy search to activate preferred RRHs for CoMP transmission. The second step forms corresponded user clusters, only a RRH j with good channel gain could be included in the serving cluster of user k. Next, in the second stage, a simple interior point method is utilised for power control. Our obtained findings confirm that the transmit power, RRH density, and the number of users served by these RRHs can significantly affect the EE. Also, the results show that under certain system settings the proposed scheme can reduce the number of active RRHs in the network by almost 13.3% compared to conventional CoMP technique applied in LTE-A standard.