Wavelet Modulation For Energy Efficient Wireless Sensors Networks with Simultaneous Wireless Information and Power Transfer

Abstract

This paper presents a Simultaneous wireless information and power transfer (SWIPT) system with dynamic power allocation (DPA). The system fills the gap in power splitting (PS) and time switching (TS) systems, where the different power requirements of running a sensor node (SN) and decoding information are overlooked. In the presented system, the energy signal is carried on an unmodulated high power continuous wave (CW) signal on the subcarriers at the carrier frequency. Similarly, the information signal is carried on the remaining low-power subcarriers, reducing the interference to external wireless networks. Moreover, at the receiver end, a separated energy harvester and information decoder design are adopted. The receiver first combines the received power from multiple antenna inputs and then splits the power between energy harvesting and information decoding circuitries. Moreover, the information signal is modulated using wavelet functions that have a better peak to average power ratio (PAPR) than the conventional OFDM rectangular window. Finally, the presented system parameters, such as data rates and the receiver’s energy harvester output, are illustrated and discussed. Furthermore, the split design showed a substantial improvement in terms of harvestable power compared to the integrated design.