A Modified COB Technique for Estimating Location in Cellular Systems with Non-Uniformly Distributed Population

Location estimation of mobile terminals under strictly non-line-of-sight propagation conditions is still an open issue. Count-of-Beacon (COB) is a new radiolocation technique where the presence of non-line-of-sight propagation does not affect the accuracy of the estimated position. In this technique, a mobile terminal´s location is realized by counting the total number of beacon packets that it can overhear. However, non-uniform distribution of mobile terminals within cells reduces the accuracy of the estimation. This paper proposes the modified version of the COB technique in which the impact of non-uniform distribution is mitigated by using the Density_Map of each cell. The introduced Density_Map divides the entire area of each cell into some regions. The estimated density-coefficients of these regions are then used to adjust the total number of overheard packets. The adjusted value closely matches the total number of packets that would likely to be overheard if cells were uniformly populated. Simulation results are used to verify the effectiveness of the proposed technique.