Full-duplex ambient backscatter with physical layer network coding

Ambient backscatter which utiliees the ambient radio-frequency signals to enable transmissions between battery-less devices has attracted considerable attention in academia and industry. This study addresses the questions of full-duplex (FD) and self-interference cancellation (SIC) for ambient backscatter which adopts dual-antenna structure to achieve persistent information transmission and energy harvesting. The authors construct the physical-layer network coding (PNC) mapping principle of on-off keying in the dual-antenna structure and propose the PNC-based FD algorithm to eliminate the self-interference in the information domain. Furthermore, the bit-error-ratio and throughput performances are analysed under conventional half-duplex mode and the proposed FD mode, respectively. In order to facilitate system complexity and reduce power consumption, they design a hardware prototype to achieve SIC which consists of low-power passive analogue components. Numerical results are provided to confirm the theoretical studies. Circuit simulations demonstrate that the circuit is commendably consistent with the design concept.