Next Article in Journal
Enhanced Sensitivity of a Hydrogen Sulfide Sensor Based on Surface Acoustic Waves at Room Temperature
Next Article in Special Issue
An Intelligent Smart Plug with Shared Knowledge Capabilities
Previous Article in Journal
A System for Generating Customized Pleasant Pedestrian Routes Based on OpenStreetMap Data
Previous Article in Special Issue
A Self Regulating and Crowdsourced Indoor Positioning System through Wi-Fi Fingerprinting for Multi Storey Building
Article Menu
Issue 11 (November) cover image

Export Article

Open AccessArticle
Sensors 2018, 18(11), 3795; https://doi.org/10.3390/s18113795

Mitigation of CSI Temporal Phase Rotation with B2B Calibration Method for Fine-Grained Motion Detection Analysis on Commodity Wi-Fi Devices

School of Environment and Society, Tokyo Institute of Technology, Tokyo 152-8552, Japan
*
Author to whom correspondence should be addressed.
Received: 10 October 2018 / Revised: 30 October 2018 / Accepted: 31 October 2018 / Published: 6 November 2018
(This article belongs to the Special Issue Wireless Sensors Networks in Activity Detection and Context Awareness)
Full-Text   |   PDF [2066 KB, uploaded 6 November 2018]   |  

Abstract

Limitations of optical devices for motion sensing such as small coverage, sensitivity to obstacles, and privacy exposure result in the need for improvement. As motion sensing based on radio frequency signals is not constrained by the limitation above, channel state information (CSI) from Wi-Fi devices could be used to improve sensing performance under the above circumstances. Unfortunately, CSI phase cannot be practically obtained due to the temporal phase rotation generated from Wi-Fi chips. Therefore, it would be rather complicated to realize motion analysis, especially the direction of motion. To mitigate the issue, this paper proposes a CSI calibration method that employs a back-to-back channel between Wi-Fi transceivers for phase rotation removal while preserving the original CSI phase. Through experiment, calibrated CSI showed a high similarity to the channel without phase rotation measured using a Vector Network Analyzer (VNA). Another experiment was conducted to observe Doppler frequency due to simple hand gestures using the Wavelet transform. A visual analysis revealed that the Doppler frequency of calibrated CSI could correctly capture the motion pattern. To the best of the authors’ knowledge, this is the first calibration method that maintains the original CSI and is applicable for in-depth motion analysis. View Full-Text
Keywords: Wi-FI; channel state information; motion sensing; device-free; phase calibration; wavelet transform Wi-FI; channel state information; motion sensing; device-free; phase calibration; wavelet transform
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Keerativoranan, N.; Haniz, A.; Saito, K.; Takada, J.-I. Mitigation of CSI Temporal Phase Rotation with B2B Calibration Method for Fine-Grained Motion Detection Analysis on Commodity Wi-Fi Devices. Sensors 2018, 18, 3795.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Sensors EISSN 1424-8220 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top