Backscatter communication with selective FSK modulation

Backscatter communication (BackCom) is known as a low-power wireless communication technology that utilizes radio frequency signal reflections instead of actively generating them. This paper introduces a novel selective Frequency Shift Keying (SFSK) modulation scheme for BackCom, aiming to simplify tag design while ensuring equivalent decoding performance at the receiver compared to the conventional pseudo FSK method employed in backscatter tags. Knowing that the transmission range is the limitation of a passive BackCom system,we focus on maximizing the distance between the emitter and tag by optimizing the reflection coefficients. To address the nonconvex nature of this optimization problem, we propose a convex approximation technique alongside an algorithm to obtain the optimized solution. Simulation results illuminate the maximum distance with the optimized reflection coefficients in various BackCom system environments and operational requirements.