Publication Type
Conference Proceeding Article
Version
acceptedVersion
Publication Date
9-2014
Abstract
Signal processing on antenna arrays has received much recent attention in the mobile and wireless networking research communities, with array signal processing approaches addressing the problems of human movement detection, indoor mobile device localization, and wireless network security. However, there are two important challenges inherent in the design of these systems that must be overcome if they are to be of practical use on commodity hardware. First, phase differences between the radio oscillators behind each antenna can make readings unusable, and so must be corrected in order for most techniques to yield high-fidelity results. Second, while the number of antennas on commodity access points is usually limited, most array processing increases in fidelity with more antennas. These issues work in synergistic opposition to array processing: without phase offset correction, no phase-difference array processing is possible, and with fewer antennas, automatic correction of these phase offsets becomes even more challenging. We present Phaser, a system that solves these intertwined problems to make phased array signal processing truly practical on the many WiFi access points deployed in the real world. Our experimental results on three- and five-antenna 802.11-based hardware show that 802.11 NICs can be calibrated and synchronized to a 20° median phase error, enabling inexpensive deployment of numerous phase-difference based spectral analysis techniques previously only available on costly, special-purpose hardware.
Keywords
Phased-array, Signal processing, NICs synchronization, Phase calibration, Angle-of-arrival, Location tracking
Discipline
Software Engineering
Research Areas
Software and Cyber-Physical Systems
Publication
MobiCom '14: Proceedings of the 20th Annual International Conference on Mobile Computing and Networking, Maui, 7-11 September 2014
First Page
153
Last Page
164
ISBN
9781450327831
Identifier
10.1145/2639108.2639139
Publisher
ACM
City or Country
New York
Citation
GJENGSET, Jon; Jie XIONG; MCPHILIPS, Graeme; and JAMIESON, Kyle.
Phaser: Enabling phased array signal processing on commodity WiFi access points. (2014). MobiCom '14: Proceedings of the 20th Annual International Conference on Mobile Computing and Networking, Maui, 7-11 September 2014. 153-164.
Available at: https://ink.library.smu.edu.sg/sis_research/2703
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Additional URL
http://doi.org/10.1145/2639108.2639139