Energy efficient pico base station switching-on/off in heterogeneous cellular network with minimum rate requirement

In this paper, we propose an algorithm that determines the optimal user equipment (UE) and base station (BS) association in heterogeneous cellular network, aiming at minimizing network energy consumption and avoiding frequent pico base station (PBS) mode switching, by taking into account the energy consumption of PBS switching-on/off operation. We first formulate the energy minimization problem into a combinatorial optimization problem, and then convert it to a linear programming problem to reduce the high computation complexity of exhaustive searching. Secondly, we propose a suboptimal algorithm to realize the PBS switching-on/off with the minimum data rate requirement of UEs, which can approach the exhaustive searching algorithm. Simulation results demonstrate that the proposed algorithm can considerably reduce the network energy consumption and thus improve the energy efficiency, compared with traditional approach. Furthermore, the proposed algorithm does not introduce frequent PBS mode switching, so that the total energy consumption is also reduced.