Multi-leveling for higher capacity of Wi-Fi backscatter communications

Backscatter communication enables a device to transmit or receive data using only the energy harvested from ambient RF signals. It can be realized via employing energy-efficient modulation and demodulation mechanisms. Specifically, a threshold-based demodulation method integrated with signal smoothing has generally been employed for backscatter communications. However, previous proposals considering a single threshold to differentiate one and zero bits from received signals have a limitation that a receiver can decode only a single bit for each demodulation attempt. Since existing Wi-Fi transceivers provide at most one RSS value per received frame, this limitation restricts the link capacity significantly. To address this limitation, we propose a simple but novel mechanism that adopts multi-leveling for Wi-Fi backscatter communications. Through computer simulation, we reveal that multi-leveling is effective in terms of BER and throughput.