A comparison of three methods to determine mobile station location in cellular communication systems

Abstract

AbstractThree methods to determine location of a mobile station in cellular communication systems are proposed and compared in this paper. The methods are introduced taking global system for mobile communications (GSM) networks as an example, although the results could be generalised for application in universal mobile telecommunications system (UMTS) networks. All three of the methods determine the mobile station location using coordinates of several base stations and corresponding timing advance (TA) parameter values. The values of the TA parameter are obtained applying the forced handover technique. The first method, the method of squares, locates the mobile station in a square region according to the data provided by one base station. The data are collected for several base stations and assembled such the mobile station is located in an intersection of the square regions, which takes a rectangular shape. This rectangle may be refined by the other two methods. The method of annuli locates the mobile station in an annular region, according to the definition of the TA parameter, while the method of circles locates the mobile station within a circular region. The region of the mobile station location is obtained as an intersection of the regions, again. In this manner, the area where the mobile station might be located is reduced. The mobile station coordinates are estimated applying a probabilistic approach, treating the mobile station coordinates as a two‐dimensional random variable. It is shown that the methods of squares and circles are robust, not being affected by indirect wave propagation, while the method of annuli provides the best localisation, but it is sensitive on indirect wave propagation. The methods are verified applying simulation of a real GSM network. Copyright © 2008 John Wiley & Sons, Ltd.