Transmission schemes and performance analysis for time-switching energy harvesting receivers

Compared with energy-harvesting transmitters, the performance of energy-harvesting receivers has not been fully investigated. The main consumption of energy at transmitters is for transmission, while that at receivers is for information decoding. Hence, the analysis and optimization of energy-harvesting transmitters and receivers are inherently different. Motivated by the above, in this paper, we analyze the performance of a time-switching energy-harvesting receiver, which switches between harvesting and decoding. We assume that the receiver can only harvest energy from the electromagnetic signal radiated by the transmitter and the energy consumption of other processing is negligible compared with decoding. 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. We address the problem of maximizing the amount of information decoded over both single and multiple blocks, and use the binary symmetric channel as an example to validate the accuracy of our analysis.