Estimating position of mobile terminals from path loss measurements with survey data

Estimating the position of mobile terminals is an important problem for cellular networks. A low cost method of locating the mobile terminal is to use measurements of the radio path loss. The distribution of radio path loss is, unfortunately, a non-linear function of the mobile terminal location. The non-linearity results from large obstacles to radio-wave propagation such as buildings or hills. This paper demonstrates how the conditional density of the location given measured path loss can be approximated as a sum of kernel density functions based on radio propagation data collected from propagation surveys or estimated from computer models. Using these approximate density functions an accurate location estimate of a mobile terminal can be estimated from measured path loss values contaminated by measurement noise. Copyright  2002 John Wiley & Sons, Ltd.