Abstract
We consider an energy harvesting point-to-point communication system where the transmitter is powered by an energy arrival process and is equipped with a finite battery of size B-max, which has limited efficiencies for storing energy into the battery and withdrawing energy from the battery. We assume a discrete i.i.d. energy arrival process where at each time step, energy of size A(i) is harvested with probability p(i), for all i is an element of {1, 2, ..., K}, independent of the other time steps. We provide upper and lower bounds on the information-theoretic capacity of this channel. These bounds are within a constant gap for K = 2 and a special case (with perfect battery efficiencies) for K = 3.