Mobile terminal location for UMTS

Interest in mobile phone location is expanding due to the implementation of the third generation (3G) multimedia phones. The initial need for accurate terminal positioning has been motivated by government authorities, mainly by the US FCC's E911 mandate for emergency services. In Europe, similar ideas have appeared but the primary interest is in commercial value-added functions. Systems resembling air navigation and secondary radar as brought down to street level and pedestrian speeds are also foreseen. This article presents an overview of UMTS mobile terminal location. The performance of standardized observed time difference of arrival (OTDOA) and a novel database correlation method (DCM) for wide bandwidth systems are evaluated through simulations in an urban microcell environment. DCM is shown to provide a reasonable location error of 25 m for 67% of the calls. The obtained respective OTDOA accuracy is 215 m only. Location problems encountered in built-up areas and relevant applications based on the obtained accuracy are discussed.