Performance of Energy-Harvesting Receivers With Time-Switching Architecture

Abstract

The analysis and optimization of energy-harvesting transmitters and receivers are different. This paper considers an end-to-end communication with an energy-harvesting receiver. The receiver has a time-switching architecture and can harvest energy from both a dedicated transmitter and other ambient radio-frequency (RF) sources. We first argue that the energy consumed for decoding (per channel use) can be expressed in terms of the gap to channel capacity and utilize this model to optimize two schemes for receiver operation. The two schemes are harvest-then-receive and harvest-when-receive, and they differ primarily in how and when they use the harvested energy for decoding. For transmission over a single block, we compare their performance from various aspects. Then we consider transmission over multiple blocks. When the energy harvested is all from the transmitter, we provide the solution for choosing the optimal code rate and fraction of channels used for energy harvesting for each block. When the energy harvested can also be from other RF sources, we provide a table-search algorithm to find a solution. Finally, we present some numerical examples to validate the accuracy of our analysis.