Simultaneous Wireless Information and Power Transfer using Rectangular Pulse and CP-OFDM

Abstract

Simultaneous wireless information and power transfer (SWIPT) has recently attracted researchers and may help satisfy future technology demands. Its principle is to let wireless power transfer (WPT) and wireless information transfer (WIT) coexist based on shared resources (or sometimes even on the same signal). SWIPT can be implemented in many different ways and the literature on the topic is very wide, each solution having different obstacles. Recent studies have shown that, due to the non linearity of the rectifiers, high-PAPR waveforms provide better performance in terms of energy harvesting; hence the design of the power signal is an important issue. In addition, the presence of this power signal should consume the smallest possible amount of resources for the information transfer. In this paper, a new waveform design is proposed where the information and power signals are superposed utilizing the same frequencies at the same time. The power signal is composed of a high peak modulated rectangular wave sent during the cyclic prefix of the CP-OFDM system such that it does not interfere with the useful OFDM data symbol duration. Interference evaluation and measurements show that a good choice of signal parameters can minimize interference on the information decoder and at the same time provide good performance in terms of energy harvesting which validates the possibility of the proposed design.