Open Access
ARTICLE
MFPL: Multi-Frequency Phase Difference Combination Based Device-Free Localization
Zengshan Tian1, Weiqin Yang1, Yue Jin1, Liangbo Xie1, *, Zhengwen Huang2
1 School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing, China.
2 Department of Electronic and Computer Engineering, Brunel University, Uxbridge, Middlesex, UK.
* Corresponding Author: Liangbo Xie. Email: .
Computers, Materials & Continua 2020, 62(2), 861-876. https://doi.org/10.32604/cmc.2020.07297
Abstract
With the popularity of indoor wireless network, device-free indoor
localization has attracted more and more attention. Unlike device-based localization
where the target is required to carry an active transmitter, their frequent signal scanning
consumes a large amount of energy, which is inconvenient for devices with limited
energy. In this work, we propose the MFPL, device-free localization (DFL) system
based on WiFi distance measurement. First, we combine multi-subcarrier characteristic
of Channel State Information (CSI) with classical Fresnel reflection model to get the
linear relationship between the change of the length of reflection path and the
subcarrier phase difference. Then we calculate the Fresnel phase difference between
subcarrier pairs with different spacing from CSI amplitude time series. Finally, we get
the change of the length of the reflection path caused by target moving to achieve
distance measurement and localization. Using a combination of subcarriers with
different spacing to achieve distance measurement effectively broadens the maximum
unambiguous distance of the system. To solve the complex non-linear problem of the
intersection of two elliptic equations, we introduce Newton's method to transform the
non-linear problem into a linear one. The effectiveness of our approach is verified
using commodity WiFi infrastructures. The experimental results show our method
achieves a median error of 0.87 m in actual indoor environment.
Keywords
Cite This Article
Z. Tian, W. Yang, Y. Jin, L. Xie and Z. Huang, "Mfpl: multi-frequency phase difference combination based device-free localization,"
Computers, Materials & Continua, vol. 62, no.2, pp. 861–876, 2020. https://doi.org/10.32604/cmc.2020.07297
Citations