Patent ID: 7398092

Claim:
A location tracing system for mobile telecommunication terminals comprising: a mobile terminal for transmitting a predetermined signal with a predetermined interval; a plurality of base stations, each calculating a distance from the mobile terminal based on a reception time of the predetermined signal transmitted from the mobile terminal; and a cell controller which traces a location of the mobile terminal based on distance values transmitted from the plurality of base stations, the cell controller coupled to the base stations and located at a position different from the location of the mobile terminal, the cell controller tracing the location of the mobile terminal by: pre-storing coordinate values for each of a plurality of regions adjacent to or including the base stations, the coordinate values for each region indicating distances between the region and respective ones of the base stations; comparing the distance values transmitted from the base stations to each of the prestored coordinate values; and determining the location of the mobile terminal as corresponding to one of said plurality of regions based on the comparison.