Marc Ciurana receives his Ph.D. degree, “Contributions to TOA-based location with WLAN”
Published August 25, 2010
On July 15th 2010 CTAE staff researcher Marc Ciurana received his Ph.D. degree in telecommunications engineering from the Universitat Politècnica de Catalunya (UPC) on the topic “Contributions to TOA-based location with WLAN” (see abstract at this end of this article). The Ph.D. thesis was started in March 2005 and has been supervised by Dr. Francisco Barceló from the Departament d’Enginyeria Telemàtica of UPC.
During his Ph.D. Marc has participated in several research projects supported by the Spanish Government (Plan Nacional de I+D and Profit) and the European Commission (IST LIAISON). He has also been teaching and mentoring several Master Thesis projects at the BCN Telecom Engineering School of UPC. He joined CTAE in November 2009 as indoor positioning researcher in the Navigation & Communications group. His main interests are in the area of location technologies for indoor environments using wireless communications networks, tracking algorithms and location-based services. He is the author and co-author of several publications in these fields and he also serves as a reviewer for international journals and conferences.
Contributions to TOA-based location with WLAN
Ph.D. Thesis abstract
Location techniques that satisfy the requirements of advanced Location-Based Services (LBS) in environments where GNSS fail, especially in indoor environments, are needed. This Ph.D. Thesis is devoted to the research on location of mobile devices employing WLAN (IEEE 802.11). The use of this kind of wireless networks infrastructures for positioning enables a powerful synergy between communications and location and allows solutions with good performances at moderated costs. However the adopted WLAN location methods suffer from important limitations that prevents from applying them to some fields that need more flexible and robust solutions. The main objective of this PhD is exploring precise WLAN location methods that allow overcoming these limitations.
The researched methods here are based on measuring the Time Of Arrival (TOA), which is the time that takes the signal propagating from the transmitter to the receiver. TOA-based location works in two stages: ranging and positioning. The ranging consists of estimating the distances between the targeted terminal and several WLAN access points, each distance obtained measuring the TOA and then multiplying it by the speed of the WLAN signal. After that, the positioning takes as inputs the estimated distances and the known coordinates of the involved access points and calculates the position of the terminal by means of a trilateration or tracking algorithm. The key problem is that the characteristics of the IEEE 802.11 protocols difficult to perform accurate TOA measurements. The main challenge that faces the research work reported here is demonstrating the feasibility of achieving this while keeping the modifications over standard WLAN consumer equipment at minimum. The objective of this work can be understood as exploring the current limits of TOA-based methods over WLAN, making contributions that form a complete TOA-based location method that goes a step forward with respect to the other existing proposals.