Abstract
Wi-Fi signals are typically information carriers between a transmitter and a receiver. In this paper, we show that Wi-Fi can also extend our senses, enabling us to see moving objects through walls and behind closed doors. In particular, we can use such signals to identify the number of people in a closed room and their relative locations. We can also identify simple gestures made behind a wall, and combine a sequence of gestures to communicate messages to a wireless receiver without carrying any transmitting device. The paper introduces two main innovations. First, it shows how one can use MIMO interference nulling to eliminate reflections off static objects and focus the receiver on a moving target. Second, it shows how one can track a human by treating the motion of a human body as an antenna array and tracking the resulting RF beam. We demonstrate the validity of our design by building it into USRP software radios and testing it in office buildings.
- How Signal is affected. www.ci.cumberland.md.us/. City of Cumberland Report.Google Scholar
- LAN/MAN CSMA/CDE (ethernet) access method. IEEE Std. 802.3--2008.Google Scholar
- LP0965. http://www.ettus.com. Ettus Inc.Google Scholar
- Nintendo Wii. http://www.nintendo.com/wii.Google Scholar
- RadarVision. http://www.timedomain.com. Time Domain Corporation.Google Scholar
- Seeing through walls - MIT's Lincoln Laboratory. http://www.youtube.com/watch?v=H5xmo7iJ7KA.Google Scholar
- Urban Eyes. https://www.llnl.gov. Lawrence Livermore National Laboratory.Google Scholar
- USRP N210. http://www.ettus.com. Ettus Inc.Google Scholar
- X-box Kinect. http://www.xbox.com. Microsoft.Google Scholar
- R. Bohannon. Comfortable and maximum walking speed of adults aged 20--79 years: reference values and determinants. Age and ageing, 1997.Google Scholar
- G. Charvat, L. Kempel, E. Rothwell, C. Coleman, and E. Mokole. A through-dielectric radar imaging system. IEEE Trans. Antennas and Propagation, 2010.Google ScholarCross Ref
- G. Charvat, L. Kempel, E. Rothwell, C. Coleman, and E. Mokole. An ultrawideband (UWB) switched-antenna-array radar imaging system. In IEEE ARRAY, 2010.Google ScholarCross Ref
- K. Chetty, G. Smith, and K. Woodbridge. Through-the-wall sensing of personnel using passive bistatic wifi radar at standoff distances. IEEE Trans. Geoscience and Remote Sensing, 2012.Google Scholar
- J. Choi, M. Jain, K. Srinivasan, P. Levis, and S. Katti. Achieving single channel, full duplex wireless communication. In ACM MobiCom, 2010. Google ScholarDigital Library
- G. Cohn, D. Morris, S. Patel, and D. Tan. Humantenna: using the body as an antenna for real-time whole-body interaction. In ACM CHI, 2012. Google ScholarDigital Library
- T. Cover and J. Thomas. Elements of information theory. Wiley-interscience, 2006. Google ScholarDigital Library
- S. Gollakota, F. Adib, D. Katabi, and S. Seshan. Clearing the RF smog: Making 802.11 robust to cross-technology interference. In ACM SIGCOMM, 2011. Google ScholarDigital Library
- S. Hong, J. Mehlman, and S. Katti. Picasso: full duplex signal shaping to exploit fragmented spectrum. In ACM SIGCOMM, 2012.Google Scholar
- M. Jain, J. Choi, T. Kim, D. Bharadia, S. Seth, K. Srinivasan, P. Levis, S. Katti, and P. Sinha. Practical, real-time, full duplex wireless. In ACM MobiCom, 2011. Google ScholarDigital Library
- H. Junker, P. Lukowicz, and G. Troster. Continuous recognition of arm activities with body-worn inertial sensors. In IEEE ISWC, 2004. Google ScholarDigital Library
- Y. Kim and H. Ling. Human activity classification based on micro-doppler signatures using a support vector machine. IEEE Trans. Geoscience and Remote Sensing, 2009.Google Scholar
- K. Lin, S. Gollakota, and D. Katabi. Random access heterogeneous MIMO networks. In ACM SIGCOMM, 2010. Google ScholarDigital Library
- B. Lyonnet, C. Ioana, and M. Amin. Human gait classification using microdoppler time-frequency signal representations. In IEEE Radar Conference, 2010.Google ScholarCross Ref
- B. Michoud, E. Guillou, and S. Bouakaz. Real-time and markerless 3D human motion capture using multiple views. Human Motion--Understanding, Modeling, Capture and Animation, 2007. Google ScholarDigital Library
- A. Oppenheim, R. Schafer, J. Buck, et al. Discrete-time signal processing. Prentice hall Englewood Cliffs, NJ:, 1989. Google ScholarDigital Library
- H. Rahul, S. Kumar, and D. Katabi. JMB: scaling wireless capacity with user demands. In ACM SIGCOMM, 2012. Google ScholarDigital Library
- T. Ralston, G. Charvat, and J. Peabody. Real-time through-wall imaging using an ultrawideband multiple-input multiple-output (MIMO) phased array radar system. In IEEE ARRAY, 2010.Google ScholarCross Ref
- S. Ram, C. Christianson, Y. Kim, and H. Ling. Simulation and analysis of human micro-dopplers in through-wall environments. IEEE Trans. Geoscience and Remote Sensing, 2010.Google Scholar
- S. Ram, Y. Li, A. Lin, and H. Ling. Doppler-based detection and tracking of humans in indoor environments. Journal of the Franklin Institute, 2008.Google Scholar
- S. Ram and H. Ling. Through-wall tracking of human movers using joint doppler and array processing. IEEE Geoscience and Remote Sensing Letters, 2008.Google Scholar
- T.-J. Shan, M. Wax, and T. Kailath. On spatial smoothing for direction-of-arrival estimation of coherent signals. IEEE Trans. on Acoustics, Speech and Signal Processing, 1985.Google Scholar
- F. Soldovieri and R. Solimene. Through-wall imaging via a linear inverse scattering algorithm. IEEE Geoscience and Remote Sensing Letters, 2007.Google ScholarCross Ref
- R. Solimene, F. Soldovieri, G. Prisco, and R. Pierri. Three-dimensional through-wall imaging under ambiguous wall parameters. IEEE Trans. Geoscience and Remote Sensing, 2009.Google ScholarCross Ref
- P. Stoica and R. L. Moses. Spectral Analysis of Signals. Prentice Hall, 2005.Google Scholar
- W. C. Stone. Nist construction automation program report no. 3: Electromagnetic signal attenuation in construction materials. In NIST Construction Automation Workshop 1995.Google Scholar
- K. Tan, H. Liu, J. Fang, W. Wang, J. Zhang, M. Chen, and G. Voelker. SAM: Enabling Practical Spatial Multiple Access in Wireless LAN. In ACM MobiCom, 2009. Google ScholarDigital Library
- D. Titman. Applications of thermography in non-destructive testing of structures. NDT & E International, 2001.Google ScholarCross Ref
- H. Wang, R. Narayanan, and Z. Zhou. Through-wall imaging of moving targets using uwb random noise radar. IEEE Antennas and Wireless Propagation Letters, 2009.Google Scholar
- J. Xiong and K. Jamieson. ArrayTrack: a fine-grained indoor location system. In Usenix NSDI, 2013. Google ScholarDigital Library
- Y. Yang and A. Fathy. See-through-wall imaging using ultra wideband short-pulse radar system. In IEEE Antennas and Propagation Society International Symposium, 2005.Google ScholarCross Ref
- Y. Yang and A. Fathy. Design and implementation of a low-cost real-time ultra-wide band see-through-wall imaging radar system. In IEEE/MTT-S International Microwave Symposium, 2007.Google ScholarCross Ref
Index Terms
- See through walls with WiFi!
Recommendations
See through walls with WiFi!
SIGCOMM '13: Proceedings of the ACM SIGCOMM 2013 conference on SIGCOMMWi-Fi signals are typically information carriers between a transmitter and a receiver. In this paper, we show that Wi-Fi can also extend our senses, enabling us to see moving objects through walls and behind closed doors. In particular, we can use such ...
Towards fine-grained radio-based indoor location
HotMobile '12: Proceedings of the Twelfth Workshop on Mobile Computing Systems & ApplicationsLocation systems are key to a rich experience for mobile users. When they roam outdoors, mobiles can usually count on a clear GPS signal for an accurate location, but indoors, GPS usually fades, and so up until recently, mobiles have had to rely mainly ...
Interference Cancellation with Space Diversity for Downlink MC-CDMA Systems
Modern wireless communications require an efficient spectrum usage and high channel capacity and throughput. Multiple-input and multiple-output (MIMO), Linear equalizers, multi-user detection and multicarrier code-division multiple access (MC-CDMA) are ...
Comments