Phaser: Enabling phased array signal processing on commodity WiFi access points

Jon Gjengset, Jie Xiong, Graeme McPhillips, Kyle Jamieson

Research output: Chapter in Book/Report/Conference proceedingConference contribution

146 Scopus citations

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. Copyright

Original languageEnglish (US)
Title of host publicationMobiCom 2014 - Proceedings of the 20th Annual
PublisherAssociation for Computing Machinery
Pages153-163
Number of pages11
ISBN (Electronic)9781450327831
DOIs
StatePublished - Sep 7 2014
Externally publishedYes
Event20th ACM Annual International Conference on Mobile Computing and Networking, MobiCom 2014 - Maui, United States
Duration: Sep 7 2014Sep 11 2014

Publication series

NameProceedings of the Annual International Conference on Mobile Computing and Networking, MOBICOM

Other

Other20th ACM Annual International Conference on Mobile Computing and Networking, MobiCom 2014
CountryUnited States
CityMaui
Period9/7/149/11/14

All Science Journal Classification (ASJC) codes

  • Software
  • Hardware and Architecture
  • Computer Networks and Communications

Keywords

  • Angle-of-arrival
  • Location tracking
  • NICS synchronization
  • Phase calibration
  • Phased-array
  • Signal processing

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  • Cite this

    Gjengset, J., Xiong, J., McPhillips, G., & Jamieson, K. (2014). Phaser: Enabling phased array signal processing on commodity WiFi access points. In MobiCom 2014 - Proceedings of the 20th Annual (pp. 153-163). (Proceedings of the Annual International Conference on Mobile Computing and Networking, MOBICOM). Association for Computing Machinery. https://doi.org/10.1145/2639108.2639139