Capacity Analysis for Wireless Symbiotic Communication Systems With BPSK Tags Under Sensitivity Constraint

Wireless symbiotic communication is an emerging green technology for Internet of Things (IoT), where batteryless devices harvest energy from ambient radio frequency (RF) signals and use backscatter technology for communications. One practical but often neglected constraint for the symbiotic communications is circuit sensitivity, below which the passive devices cannot harvest energy. In this letter, we focus on the capacity analysis under the constraint of sensitivity. Specifically, we first build up the mathematical model for the wireless symbiotic communication system, then derive its channel capacity considering the sensitivity constraint, and compare the capacity performance with the existing symbiotic communication systems without sensitivity constraint and also the traditional point-to-point systems. Simulations are then provided to corroborate our proposed studies.