Does Ambient Backscatter Need Additional Regulations?

Ambient Backscatter Communication (AmBC) is an emerging ultra-low power communication scheme which enables smart devices to communicate by modulating ambient radio frequency (RF) signals without requiring active RF transmission. AmBC can be interpreted as a spectrum sharing system that AmBC devices share the spectrum with the incumbent wireless broadcast systems. In this paper, we study the impact of AmBC from the incumbent receiver perspective since AmBC introduces a new situation for regulators. In the analysis, we consider a generic Orthogonal Frequency Division Multiplexing based broadcast broadcast system that corresponds to digital audio or video broadcasting or downlink of a mobile communication system. Broadcasting spectrum can be used by unlicensed transmitters in television white space framework. Contrary to the television white space transmitters that always cause interference to the incumbent system, the impact of AmBC depends on the equalization interval of the receiver. The incumbent receiver sees an AmBC device as an additional fast fading multi-path component. AmBC can sometimes even contribute positively to the received signal quality. Our results suggest that in many practical scenarios AmBC systems can co-exist with digital broadcast systems without causing harmful interference.