Dynamic Power Allocation for a Hybrid Energy Harvesting Transmitter with Multiuser in Fading Channels

In this work, we consider a multiuser communication system in fading channels where the transmitter is supplied by hybrid energy sources including power grid and various renewable sources. Specially, the energy harvested from various renewable sources is stored in a limited capacity buffer, and the joint energy incoming is time-varying and possibly unpredictable. In addition, data arrives randomly to the transmitter and queues according to the individual receivers, the wireless channels fluctuate randomly due to fading. Our goal is, under this condition to develop a dynamic power allocation algorithm so as to minimize the time average amount of energy consumed from the power grid over an infinite horizon, subjecting to all data queues stability. The issue is formulated as a stochastic optimization problem and solved by Lyapunov optimization technique which does not require the statistical probabilities of energy harvesting process, data arrivals process and channel state. Simulation results demonstrate that our proposed algorithm provides obviously better performance than other two simple greedy algorithms, meanwhile the algorithm gives a guarantee that the maximum delay of all data queues cannot exceed a given value.