Device and method for locating a mobile station in a mobile communication system

Abstract

A device and method for locating a mobile station (MS) in a mobile communication system. In the MS locating device, a first antenna and a second antenna of a base station (BS) are spaced from each other by a distance equivalent to a wavelength of an MS transmission channel multiplied by a predetermined coefficient, such as one half. A first frequency downconverter and a second frequency downconverter convert signals received from the first and second antennas to baseband signals and digitize the baseband signals to chip sample data. A first channel demodulator and a second channel demodulator recover the chip sample data received from the first and second frequency downconverters and output information about the symbol start and PN code of a specific MS signal. A controller outputs a PN code for identifying the specific MS and finger position information based on the symbol start and PN code information received from the first and second demodulators. In addition, the controller may be supplied with orthogonal code information from the demodulator; in this case, the controller will output information concerning the specific Walsh code. A symbol data extractor extracts two symbols of the specific MS from the chip sample data received from the first and second frequency downconverters based on the PN code and finger position information. An incident angle estimator estimates the incident angle of the received signal from the phase difference between the extracted two symbols. A location estimator estimates the location of the specific MS based on the estimated incident angle and the round trip delay (RTD) measured for the MS.