On the Optimality of Green Cell Load and Throughput in Small Cell Networks with Weighted Channel-Aware Cell Association

The fundamental interactions between cell association, cell throughput and load in a green (energy-efficient) small cell network are exploited in this paper. Due to user-centric cell association, a small cell network severely suffers the void cell problem. We propose a weighted channel-aware cell association (WCCA) scheme and derive the average cell throughput under this scheme that characterizes the per-cell throughput with the void cell impact. We show that the average throughput is significantly affected by WCCA and cell load. In order to reflect whether the energy of a base station is efficiently used to transmit information or not, the green cell throughput, which is defined based on the average cell throughput, is derived and it indicates that cell load should be properly determined in order to achieve the satisfactory green cell throughput. The theoretical solution of the optimal cell load that maximizes the green cell throughput is found and verified its correctness by simulation.