Dynamic User-Centric Clustering Algorithm Based on Energy Efficiency in Cloud-RAN

This paper studies user-centric cluster scheme in cloud radio access network (Cloud-RAN), where distributed Radio Remote Heads (RRHs) are connected to a centralized Based Band Units (BBUs) pool and all baseband processing is performed via high-bandwidth low-latency backhaul network. In user-centric cluster scheme, BBU schedules multiple RRHs for each user to form the serving cluster, and then BBU pool distributes the user's data to the cluster via backhaul link. By taking into account signal-to-interference-and-noise ratio (SINR) constraint for each user and transmit power constraint for per-RRH, we design a cluster scheme aiming at maximizing network energy efficiency (EE). And then weighted minimal mean square error (WMMSE) method are adopted to transform the original problem into a tractable form. Specially, a sparsity-based dynamic user-centric cluster algorithm is proposed, where the cluster for each user can change over time according to network EE performance. Simulation results show that the proposed algorithm can effectively form the serving cluster according to user's QoS demand and greatly improve the network energy efficiency.