Online Power Control for Block i.i.d. Bernoulli Energy Harvesting Channels

This work studies the problem of online power control for energy harvesting systems with random energy arrivals and a finite battery. The stochastic model for the energy arrivals is block i.i.d., in which the energy arrivals are constant for a fixed duration, but can change independently between different blocks. We propose a simple online power control policy for the case of Bernoulli energy arrivals, and prove that its performance gap to the optimal throughput is bounded by a constant which is independent of the parameters of the problem. This also yields a simple formula for the approximately optimal long-term average throughput, which sheds some light on the qualitative behavior of the throughput and how it depends on the ``coherence time'' of the energy arrival process. Specifically, this formula exhibits different behavior in three different regimes, depending on the parameters of the communication system.