Online power control strategy for wireless transmission with energy harvesting

We consider data transmission with energy harvesting and storage devices over wireless fading channel. We design an online power control strategy aiming at maximizing the long-term time-averaged data rate, given finite battery storage and operation constraints. Through problem transformation and Lyapunov optimization technique, we develop an online algorithm to determine transmit power based on the current energy level of the battery and channel fade condition. Our power solution does not rely on any knowledge of the statistics of energy arrivals and fading channel. It is provided in closed-form which not only provides insight to the energy management and transmission control actions, but also has minimum complexity for implementation. We further bound the performance of our proposed algorithm to that of the optimal solution. Simulation results demonstrate significant performance gain of the proposed strategy over the greedy approach.