Evaluation of Maximum Range for Backscattering Communications Utilising Ambient FM radio signals

The objective of this article is to evaluate the maximum range of ambient backscattering communications (AmBC). FM radio signals operating at 100 MHz are selected as the ambient signal due to their large communication ranges. The FM radio signals operate in one of the lowest commercially available frequency bands that can be utilized for AmBC. Additionally, due to the extensive deployment of FM radio, this technology is readily available worldwide. Simulations are performed in a rural highway environment to analyse the suitability of FM radio as an ambient signal for backscattering communications. The FM transmitter and receiver antenna are located in approximately the same area representing a monostatic form of operation for backscattering communications. The sensors are located in more or less the line of sight (LOS) of the TX/RX antenna. The FM signal is reflected back from the sensor towards the receiver for detection. The ray-tracing technique and the radar equation are utilized to perform the simulations. Based on the ray-tracing simulations, a distance of 14.5 km was obtained between the TX/RX antenna and the sensor. The achievable distances utilising the radar equation depend significantly on the cross-section of the sensor and different sizes were utilised in the simulations.