Signal Detection Method Based on Peak to Average Ratio for Frequency Shift Multitone SWIPT System

Battery-less devices that operate on wireless power transfer have a relatively small operating area due to the limited transmit power from the source. Multitone based waveforms are considered to be one of the techniques to expand this operating range. However, they require some bandwidth to achieve this feature. By sharing the bandwidth required for multitone waveforms and superimposing information on the power, it is possible to transmit both power and information at the same time, which is known as simultaneous wireless information and power transfer (SWIPT). In this paper, we introduce a method of detecting signal by measuring peak to average power ratio (PAPR) in order to reduce the computational cost for frequency shift keying type SWIPT instead of observing frequency-domain signals by using fast Fourier transforms. Signal decoding is possible by seeing the PAPR difference as the frequencies of intermodulation signals varies with difference tone arrangement. We demonstrate this through circuit simulation with Advanced Design Systems (ADS) and show how many bits could encode for tones of 3 and 4. In addition, we categories which tone variations in the frequency domain would lead to obtaining a specific PAPR at the receiver end.