Outage probability optimization with equal and unequal transmission rates under energy harvesting constraints

In this paper, we study the power scheduling problem to optimize the outage probability with both equal and unequal transmission rates under energy harvesting constraints. In particular, we first model the average outage probability minimization problem over finite horizon, and then reformulate the problem by minimizing its upper bound, which converts the non-convex problem to a more efficient convex optimization problem. Next, we show the optimal power scheduling solution is related to the global minimum of an energy-and-time function which is defined as arithmetic average of harvested energy from current time slot to the arbitrary time slot in the future before the end of transmission. Based on such properties, we propose a Min-Average strategy which presents the optimal performance in upper bound of outage probability for equal and non-equal transmission rates. Simulation results show that, our power scheduling scheme achieves better outage performance compared to other alternative strategies, e.g, best-effort, fixed-saving and random saving strategies.