Network Based Mobile Station Positioning in Metropolitan Area

Recently, mobile station positioning is drawing considerable attention in the field of wireless communications. Many location estimation techniques have been proposed. Although location estimation algorithms based on received signal strength technique may not be the most promising approach for providing location services, signal strength is the only common attribute available among various kind of mobile network. In this paper, we report our study of a Crude Estimation Method (CEM) which estimate the location of a mobile station based on the ratio of the signal strengths received from different base transceiver stations. We conducted series of field tests with the networks of two major mobile phone operators of Hong Kong. Among 6120 real world readings obtained from these field tests, the average errors of CEM is 49.03 meter with a variance of 538.14. When comparing the results of CEM with the Center of Gravity Method (CGM), another mobile location estimation also based on signal strength ratio, CEM has an improvement of 33.85% with about the same variance. These results are very encouraging in the study of mobile network based mobile station positioning in metropolitan areas.