Time of Arrival Estimation for Backscatter UWB

Backscatter communication, a passive transmission technique, is widely employed in Internet of Things (IoT). For localization purpose, Ultra-Wideband (UWB) technology offers large bandwidth and high time domain resolution, making it ideal for various positioning applications in IoT. In this letter, we show that the time indices of the backscatter UWB pulses are topologically correlated in multipath propagation environments. Based on this, we propose a novel TOA estimation method which can dramatically improve the estimation accuracy in practical SNR regimes. To our best knowledge, this is the first time that a TOA estimator for backscatter UWB is proposed by taking the advantage of the topological structure of the time indices of the pulses.

I. Introduction

One essential characteristic that future Internet of Things (IoT) devices must embody is low power consumption coupled with wireless power transfer, facilitating their widespread deployment [1], [2]. Backscatter communication (BSC) is an emerging technology for IoT, that can help realize green, low-cost and sustainable communications. A BSC system typically consists of a reader and a tag. As shown in Fig. 1, the reader sends an unmodulated wave to the tag, and the tag utilizes RF signal energy to charge and then reflects its signal by altering antenna impedance loading. The reader receives bascattered signal and then decodes the information from tag.