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RF-CoHetNet: An Architecture for Cognitive Heterogeneous Networks Powered by RF-Energy

Energy efficiency is an important focus area of 5G mobile technology. Due to global warming, it is important to lower the global CO2 footprint, even with the expectation of massively increasing cellular data traffic. The ability of HetNets to support high capacity makes it a significant driver for the success of 4G and indispensable in 5G. Small cells equipped with cognitive radio (CR) techniques could improve spectrum utilization by opportunistic spectrum access and intelligent interference mitigation. In this article, we propose an RF-CoHetNet, a novel heterogeneous cellular network system where small cells possess CR capabilities and are wirelessly powered by electromagnetic RF-energy. Under this system architecture, both energy efficiency and spectral efficiency can be achieved by properly switching small cells to harvesting mode or allocating channels/power to serve their users. We show that RF-energy harvesting can provide a promising solution to further improve the energy efficiency of the whole system. Through RF-energy harvesting, the unavoidable interference turns out to be a useful energy resource to support partial power consumption in the small cell. We further propose a heuristic algorithm to minimize the total system energy consumption under the system capacity constraint. From the numerical results, we give some insights into the possibility of RF-CoHetNet deployment.