Iterative greedy algorithms for energy efficient LTE small cell networks

The increasing demand for high bandwidth in cellular wireless networks led to a dramatic increase in the number of deployed LTE femtocell base stations (FBS) in recent years. While the energy consumed by a single FBS is relatively negligible, the collective energy footprint of all FBSs deployed by an operator turns out to be huge. Energy-efficient protocols are needed thus to balance the trade-off between energy saving and bandwidth utilization. The key component of the desired protocol to prevent both energy and bandwidth waste is interference mitigation, which, most previous work has failed to properly consider. To this end, in this paper, we manipulate user equipment (UE) association and OFDMA scheduling with a combination of interference mitigation to enable an energy efficient QoS-constrained medium access for femtocell networks. Recognizing the NP-hardness of the problem, we propose two algorithms with guaranteed convergence. Extensive simulations show that our algorithms outperform alternatives in multiple metrics such as utility, power consumption, and convergence speed.