On Measurement of the Spatio-Frequency Property of OFDM Backscattering

TL;DR

This paper studies the spatial and frequency characteristics of OFDM backscatter systems, analyzing how distance and angle affect signal strength to optimize tag placement for better IoT connectivity.

Contribution

It provides empirical measurements of OFDM backscatter signal strength across different spatial and frequency configurations, guiding optimal deployment strategies.

Findings

Optimal tag placement is near the transmitter or receiver depending on frequency.

The best angle between transmitter and receiver is 90 degrees.

Spatial deployment impacts backscatter performance and interference.

Abstract

Orthogonal frequency-division multiplexing (OFDM) backscatter system, such as Wi-Fi backscatter, has recently been recognized as a promising technique for the IoT connectivity, due to its ubiquitous and low-cost property. This paper investigates the spatial-frequency property of the OFDM backscatter which takes the distance and the angle into account in different frequency bands. We deploy three typical scenarios for performing measurements to evaluate the received signal strength from the backscatter link. The impact of the distances among the transmitter, the tag and the receiver, as well as the angle between the transmitter and the tag is observed through the obtained measurement data. From the evaluation results, it is found that the best location of tag is either close to the receiver or the transmitter which depends on the frequency band, and the best angle is 90 degrees between the transmitter and the receiver. This work opens the shed light on the spatial deployment of the backscatter tag in different frequency band with the aim of improving the performance and reducing the interference.