Energy efficiency optimization in OFDMA heterogeneous networks with RF energy harvesting

In this paper, the power allocation problem, which aims to optimize the energy efficiency (EE) of downlink OFDMA heterogeneous networks, is researched. Specifically, the terminals are sensor nodes in the Internet of Things (IoT) with RF energy harvesting (EH) technology. This technology enables the sensor nodes to capture energy from the wireless signals in air, constitutes a permanent energy source, and provides self-stainability to them. Traditional interference analysis and EE modeling are unsuitable for our EH introduced problem, so we model the energy-efficient power allocation problem as an EH based non-cooperative (EHNC) game. Then we prove the existence and reveal the uniqueness conditions of the EHNC game equilibrium. We propose a distributed energy-efficient power allocation algorithm to solve the problem, and reveal that the game can converge to Nash equilibrium after certain times of iterations. Simulation results show that the proposed algorithm is effective in increasing energy-efficient performance, harvesting energy and guaranteeing QoS of the IoT sensor nodes simultaneously.