Enhanced Observed Time Difference Location Technology Through Fading Channels in GSM Networks

摘要

This study presents a communications model that investigates the position accuracy of a Global Standard Mobile (GSM) phone employing the Enhanced Observed Time Difference (EOTD) location technology. The EOTD positioning technique requires the Mobile Station (MS) to detect signals from at least three Base Stations (BS). This study assumes the three BSs are synchronized in time. For a given BS geometry with respect to the MS, a Monte Carlo simulation was performed to assess the two-dimensional position accuracy of the MS in Rayleigh and Ricean fading channels. In each channel, a Monte Carlo simulation was performed for a good and a bad BS-to-MS geometry. Location-based services have been standardized for incorporation into 3rd generation wireless communications as a result of the Federal Communications Commission`s (FCC) mandate on wireless carriers to provide Automatic Location Information (ALI) during emergency 911 calls. This mandate has driven the wireless carriers to explore terrestrial, satellite and hybrid based location technology solutions. The study concludes with the fact that EOTD as the primary location technology does not fulfill the FCC E911 mandate and Hybrid technologies might overcome the EOTD limitations.