Online Scheduling for Energy Harvesting Channels With Processing Costs

Abstract

We consider scheduling for energy harvesting channels in which the users incur processing cost per unit time that they are on. The presence of processing costs forces the users to operate in a bursty mode. We consider online transmission scheduling where the users know the energy harvests only causally as they happen, and need to determine the optimum transmit powers and the optimum burst durations on the fly. We first consider the single-user channel. For this case, we first consider the case of independent and identically distributed (i.i.d.) Bernoulli energy arrivals, and then extend our analysis to the case of general i.i.d. energy arrivals. We determine the exactly optimum online policy for Bernoulli arrivals and propose a nearly optimum online policy for general arrivals. The proposed policy is near-optimum in that it performs within a constant gap from the optimum policy for all energy arrivals and battery-sizes. We then extend our analysis to the case of two-way energy harvesting channels with processing costs; in this case, the users incur processing costs for being on for transmitting or receiving data. We consider the case where the users harvest energy from fully correlated energy sources. We determine the exactly optimum online power schedule for i.i.d. Bernoulli energy arrivals and develop a nearly optimum online power schedule for general i.i.d. energy arrivals. Our proposed policy is distributed, which users can apply independently with no need for cooperation or coordination between them.