The Two-User Gaussian Interference Channel With Energy Harvesting Transmitters: Energy Cooperation and Achievable Rate Region

This paper studies the symmetric two-user Gaussian interference channel where the transmitters harvest randomly arrived energies and share the harvested energy with each other for energy cooperation. We characterize the achievable average rate region of the interference channel with time-varying available power when the simplified Han-Kobayashi scheme, known as a near-optimal transmission strategy for the conventional two-user Gaussian interference channel, is employed. We prove that each corner point on the average rate region is on a sum rate bound with appropriate power allocation. Based on the proof, we find the optimal strategy of energy cooperation and power allocation between the two transmitters to achieve the boundary points on the average rate region. It is shown that the energy cooperation can enlarge the average rate region compared to that of the conventional interference channel. We also show that the energy cooperation yields almost the same average rate region regardless of the interference channel condition because it enables to effectively change the given interference channel condition into a more favorable one by flexibly controlling the transmit powers.