Abstract
In this paper we present how motion sensing can be obtained just by observing the WLAN radio signal strength and its fluctuations. The temporal, spectral and spatial characteristics of WLAN signal are analyzed. Our analysis confirms our claim that ’signal strength from access points appear to jump around more vigorously when the device is moving compared to when it is still and the number of detectable access points vary considerably while the user is on the move’. Using this observation, we present a novel motion detection algorithm, Spectrally Spread Motion Detection (SpecSMD) based on the spectral analysis of WLAN signal’s RSSI. To benchmark the proposed algorithm, we used Spatially Spread Motion Detection (SpatSMD), which is inspired by the recent work of Sohn et al.Both algorithms were evaluated by carrying out extensive measurements in a diverse set of conditions (indoors in different buildings and outdoors - city center, parking lot, university campus etc.,) and tested against the same data sets. The 94% average classification accuracy of the proposed SpecSMD is outperforming the accuracy of SpatSMD (accuracy 87%). The motion detection algorithms presented in this paper provide ubiquitous methods for deriving the state of the user. The algorithms can be implemented and run on a commodity device with WLAN capability without the need of any additional hardware support.
This is a preview of subscription content, log in via an institution to check access.
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
References
Anderson, I., Muller, H.: Context Awareness via GSM Signal Strength Fluctuation. In: the 4th International Conference on Pervasive Computing, Late breaking results. Oesterreichische Computer Gesellschaft, pp. 27–31 (May 2006)
Randell, C., Muller, H.: Context awareness by analysing accelerometer data. In: MacIntyre, B., Iannucci, B. (eds.) The Fourth International Symposium on Wearable Computers, pp. 175–176. IEEE Computer Society, Los Alamitos (2000)
Krumm, J., Horvitz, E.: LOCADIO: Inferring Motion and Location from Wi-Fi Signal Strengths. In: Mobiquitous 2004. First Annual International Conference on Mobile and Ubiquitous Systems: Networking and Services, pp. 4–13 (August 2004)
Weisstein, E.W.: Spearman Rank Correlation Coefficient. From MathWorld–A Wolfram Web Resource, http://mathworld.wolfram.com/
Bahl, P., Padmanabhan, V.N.: Radar: An in-building rf-based user location and tracking system. In: Proceedings of the IEEE Infocom 2000, Tel-Aviv, Israel, vol. 2, pp. 775–784 (March 2000), http://citeseer.ist.psu.edu/bahl00radar.html
LaMarca, A., Chawathe, Y., Consolvo, S., Hightower, J., Smith, I., Scott, J., Sohn, T., Howard, J., Hughes, J., Potter, F., Tabert, J., Powledge, P., Borriello, G., Schilit, B.: Place Lab: Device Positioning Using Radio Beacons in the Wild. In: Gellersen, H.-W., Want, R., Schmidt, A. (eds.) PERVASIVE 2005. LNCS, vol. 3468, pp. 225–242. Springer, Heidelberg (2005)
Muthukrishnan, K., Meratnia, N., Lijding, M., Koprinkov, G., Havinga, P.: WLAN location sharing through a privacy observant architecture. In: 1st International Conference on Communication System Software and Middleware (COMSWARE), paper no 43, IEEE Communication Society Press, Los Alamitos, California (2006)
Sohn, T., Varshavsky, A., LaMarca, A., Chen, M.Y., Choudhury, T., Smith, I., Consolvo, S., Hightower, J., Griswold, W.G., de Lara, E.: Mobility Detection Using Everyday GSM Traces. In: Proceedings of the Eighth International Conference on Ubiquitous Computing. Irvine, California, pp. 212–224 (September 2006)
Liao, L., Patterson, D.J., Fox, D., Kautz, H.: Inferring High-Level Behavior from Low-Level Sensors. In: Dey, A.K., Schmidt, A., McCarthy, J.F. (eds.) UbiComp 2003. LNCS, vol. 2864, pp. 73–89. Springer, Heidelberg (2003)
Hashemi, H.: The Indoor Radio Propagation Channel. Proceedings of IEEE 81(7) (July 1993)
Hightower, J.: The Location Stack, Phd Thesis, University of Washington (2004)
Exahau Positioning System, http://www.ekahau.com
Air Location II, http://www.engadget.com/2006/10/02/hitachis-employee-tracking-airlocation-ii-tag-w-wifi-enabled-rf/
Welch, G., Foxlin, E.: Motion tracking: No silver bullet, but a respectable arsenal. IEEE Comput. Graph. Appl. 22(6), 24–38 (2002)
Smart Surroundings, http://wwwes.cs.utwente.nl/smartsurroundings/
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 2007 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Muthukrishnan, K., Lijding, M., Meratnia, N., Havinga, P. (2007). Sensing Motion Using Spectral and Spatial Analysis of WLAN RSSI. In: Kortuem, G., Finney, J., Lea, R., Sundramoorthy, V. (eds) Smart Sensing and Context. EuroSSC 2007. Lecture Notes in Computer Science, vol 4793. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-75696-5_4
Download citation
DOI: https://doi.org/10.1007/978-3-540-75696-5_4
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-75695-8
Online ISBN: 978-3-540-75696-5
eBook Packages: Computer ScienceComputer Science (R0)