Recent advances in energy harvesting technologies enable wireless devices to harvest the energy they need from the natural resources in their environment. This development opens the exciting new possibility to build wireless networks that are self-powered, self-sustainable and which have lifetimes limited by their hardware and not the size of their batteries.
However, energy harvesting also brings a fundamental shift in communication system design principles. In conventional systems, energy (or power) is a deterministic quantity continuously available to the transmitter and communication is typically constrained only in terms of average power. In harvesting systems, the energy available for communication is a stochastic rather than a deterministic process which has memory and is input-dependent. In this talk, we will investigate the information-theoretic capacity of this non-traditional communication system. We will characterize the capacity as an n-letter mutual information rate under various assumptions on the availability of energy arrival information and use these n-letter expressions to approximate the capacity in terms of a power control problem that has been extensively studied in the recent communication theory literature. We will then proceed to deriving an approximate solution to this power control problem which will allow us to approximate the capacity with a simple and insightful formula within a constant gap independent of system parameters.
Joint work with Dor Shaviv, Phan-Minh Nguyen and Yishun Dong.