Extracting Range-Doppler Information of Moving Targets from Wi-Fi Channel State Information

TL;DR

This paper introduces a novel signal processing method to extract accurate range and Doppler information of moving targets using standard Wi-Fi CSI, overcoming hardware and coupling challenges with commercial hardware.

Contribution

The paper presents a new approach for Wi-Fi sensing that enables high-precision range and Doppler estimation with off-the-shelf hardware, addressing phase errors and antenna coupling.

Findings

Achieves cm-level accuracy in range and Doppler estimation.

Successfully detects and tracks moving objects in realistic environments.

Validates method using commercial Intel Wi-Fi NIC without hardware modifications.

Abstract

This paper presents, for the first time, a method to extract both range and Doppler information from commercial Wi-Fi Channel State Information (CSI) using a monostatic (single transceiver) setup. Utilizing the CSI phase in Wi-Fi sensing from a Network Interface Card (NIC) not designed for full-duplex operation is challenging due to (1) Hardware asynchronization, which introduces significant phase errors, and (2) Proximity of transmit (Tx) and receive (Rx) antennas, which creates strong coupling that overwhelms the motion signal of interest. We propose a new signal processing approach that addresses both challenges via three key innovations: Time offset cancellation, Phase alignment correction, and Tx/Rx coupling mitigation. Our method achieves cm-level accuracy in range and Doppler estimation for moving targets, validated using a commercial Intel Wi-Fi AX211 NIC. Our results show successful detection and tracking of moving objects in realistic environments, establishing the feasibility of high-precision sensing using standard Wi-Fi packet communications and off-the-shelf hardware without requiring any modification or specialized full-duplex capabilities.