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AWL: Turning Spatial Aliasing From Foe to Friend for Accurate Wi-Fi Localization
Date: 2017/11/29             Browse: 290

Speaker:     Associate Prof. Yuedong Xu, Fudan University

Time:           Nov  29 ,  16:00 – 17:00

Location:    Auditorium, SIST Building

Host:           Prof. Ziyu Shao


Owing to great potential in smart home and human-computer interactive applications, Wi-Fi indoor localization has attracted extensive attentions in the past several years. The state-of-the-art systems have successfully achieved decimeter-level accuracies. However, the high accuracy is acquired at the cost of dense access point (AP) deployment, employing large size of frequency bandwidths or special purpose radar signals which are not compatible with existing Wi-Fi protocol, limiting their practical deployments. This paper presents the design and implementation of AWL, an accurate indoor localization system that enables a single Wi-Fi AP to achieve decimeter level accuracy with only one channel hopping. The key enabler of the system is we novelly employ channel hopping to create virtual antennas, without the need of adding more antennas or physically move the antennas’ positions for a larger antenna array. We successfully utilize the widely known "bad" spatial aliasing to improve the AoA estimation accuracy. A novel multipath suppression scheme is also proposed to combat the severe multipath issue indoors. We build a prototype of AWL on WARP software-defined radio platform. Comprehensive experiments manifest that AWL achieves a median localization accuracy of 38 cm in a rich multipath indoor environment with only a single AP equipped with 6 antennas. In a small scale area, AWL is able to accurately track a moving device's trajectory, enabling applications such as writing/drawing in the air. 


Yuedong Xu is an associate professor in School of Information Science and Technology, Fudan University, China. He received his PhD from The Chinese University of Hong Kong, M.S. degree from Huazhong University of Science and Technology and B.S. degree from Anhui University. From late 2009 to 2012, he was a postdoc with INRIA Sophia Antipolis and Universite d'Avignon, France. His areas of interest include system design, performance evaluation, data analytics and economic analysis for communication networks. 

SIST-Seminar 17062