Optimising the BBU pool placement in cloud radio access networks based on power allocations

The placement of the base band unit pool (BBU pool) in cloud-radio access networks (C-RANs) is an important and crucial issue. The optimal position of the BBU pool can offer enhanced spectral efficiency (SE), received data rates and QoS for the UEs. This paper uses particle swarm optimization (PSO) to evaluate the sub-optimal solution of the BBU pool that maximises the sum of users' spectral efficiency (SE). The system model included both an optical and wireless links from the pool to the RRHs. The performance of two cases is compared under two simulation scenarios. The first is the dynamic remote radio heads (RRHs) and the dynamic users (UEs), in which, several UEs and RRHs' locations snapshots and resources assignment possibilities were considered by integrating Monte Carlo simulation and PSO algorithm. The second scenario considers the RRHs to static locations while the UEs' locations are dynamic, in this case, the algorithm considers only the UEs assignment possibilities. In each type of links and each scenario, two power allocation methods (PMs) have been proposed to distribute the power from BBU pool into RRHs while considering the fiber and signalling overhead losses.