Delay Estimation for Ranging and Localization Using Multiband Channel State Information

TL;DR

This paper introduces a high-resolution delay estimation algorithm leveraging multiband channel state information in wireless networks, significantly improving localization accuracy over traditional methods with limited bandwidth.

Contribution

It develops a novel delay estimation algorithm based on multiband CSI and shift-invariance, achieving near CRB performance and validated with real indoor measurements.

Findings

Achieves less than 0.3 ns RMSE in delay estimation

Algorithm converges to the Cramér-Rao Bound asymptotically

Validates effectiveness with real indoor channel data

Abstract

In wireless networks, an essential step for precise range-based localization is the high-resolution estimation of multipath channel delays. The resolution of traditional delay estimation algorithms is inversely proportional to the bandwidth of the training signals used for channel probing. Considering that typical training signals have limited bandwidth, delay estimation using these algorithms often leads to poor localization performance. To mitigate these constraints, we exploit the multiband and carrier frequency switching capabilities of wireless transceivers and propose to acquire channel state information (CSI) in multiple bands spread over a large frequency aperture. The data model of the acquired measurements has a multiple shift-invariance structure, and we use this property to develop a high-resolution delay estimation algorithm. We derive the Cram\'er-Rao Bound (CRB) for the data model and perform numerical simulations of the algorithm using system parameters of the emerging IEEE 802.11be standard. Simulations show that the algorithm is asymptotically efficient and converges to the CRB. To validate modeling assumptions, we test the algorithm using channel measurements acquired in real indoor scenarios. From these results, it is seen that delays (ranges) estimated from multiband CSI with a total bandwidth of 320 MHz show an average RMSE of less than 0.3 ns (10 cm) in 90% of the cases.