Localization in wireless WLAN Networks with Propagation Delay Measurement

Description

Localization in WLAN networks is finding the position of a mobile node, using the properties of a wireless network (radio signal strength, propagation delay, information about the neighbours, etc.). Localization is used for various purposes ranging from personal navigation systems to finding the position of an emergency call. Location-aware services increase the value of existing wireless network infrastructures.

Most of the methods for wireless LAN localization known in the literature use radio signal strength indication (RSSI) in order to estimate position [1,2,4]. However, the dependency of signal strength on distance is non-linear but specific for the environment [3,4]. Therefore, these methods mostly lack precision or a possibility for automation.

On the other hand, the dependency between signal propagation time and distance is linear [3]. Therefore, the methods based on propagation time promise a better precision. However, the main problem by such approaches is the exact measurement of time. Since the radio waves propagate with the speed of light (1 meter for 3.3 nanoseconds), it is required to measure times with a precision in the magnitude of nanoseconds.

This seminar topic considers methods for wireless LAN localization, which guess distance and position, by measuring or estimating the radio signal propagation time. The scientific work [3] can be used as a starting point. All references are available on request.

This topic requires knowledge in the following fields: wireless networks, communication technology, and statistics.

References

1. P. Bahl and V. N. Padmanabhan. RADAR: An In-Building RF-Based User Location and Tracking System. IEEE Infocom, 2000.
2. Ekahau Positioning Engine
3. André Günther and Christian Hoene. Measuring Round Trip Times to Determine the Distance between WLAN Nodes. In NETWORKING 2005: Proceedings of the 4th International IFIP-TC6 Networking Conference, 2005. Springer Verlag.
4. Moustafa Youssef and Ashok Agrawala. The Horus WLAN Location Determination System. In MobiSys '05: Proceedings of the 3rd international conference on Mobile systems, applications, and services, 2005. ACM Press.

Contact

Svilen Ivanov