US 6,477,380 B1 · System and method for estimating location of mobile station

Abstract

There has been such a drawback that it is difficult to accurately estimate the location of mobile station MS in a mobile communication system. To solve the problem, according to the mobile communication system of the present invention, a mobile station and several base station cooperate for estimation. First the base stations BS in which the mobile station is laid and other base stations adjacent thereto each measure the receipt levels of the radio wave radiated by the mobile station to notify the position manage center of the receipt levels. Second the position manage center instructs the mobile station to control the radio wave pursuant to the receipt levels in such a fashion the receipt levels are stabilized; finally. Third each base station measure the distance between the base station and the mobile station based upon the propagation time of the radio wave to inform the position manage center of the distance. Finally, the position manage center estimates the location of the mobile station based upon a point or several points given by the circles defined using the distances.

Claims27

Dependent claims

A mobile communication system including a plurality of base stations transmitting and receiving a frame to/from a mobile station, and a manage station managing the plurality of base stations, and wherein:

of the base stations comprises
a distance measuring circuit that measures a distance between a respective base station and the mobile station using a radio wave from the mobile station, and notifies the manage station of the distance, and
a receipt level measuring circuit that measures the receipt level of the radio wave and notifies the manage station of the receipt level;
the manage station comprises
an estimating circuit that estimates the location of the mobile station based upon a plurality of distances measured by the plurality of base stations,
an instructing circuit that instructs the mobile station to control a transmission power of the radio wave so that the plurality of respective receipt levels of the plurality of base stations exceed a threshold, and
a departure time notifying circuit that notifies the plurality of base stations of the departure time of the radio wave;
and
the mobile station comprises
a power control circuit that controls the transmission power of the radio wave pursuant to the instructions from the manage circuit received via a base station with a receipt level which exceeds the threshold.

7 more elements

A method of estimating the location of a mobile station in a mobile communication system in which the mobile station and a plurality of base stations communicate with each other, the method comprising:

selecting the base stations for measuring distances between the base station and the mobile station;
checking a receipt level of a radio wave radiated from the mobile station and received by the base stations;
controlling a transmission power of the radio wave radiated from the mobile station by comparing the receipt level at the base station with a given threshold and increasing the transmission power of the radio wave until the given threshold value is exceeded;
notifying the plurality of base stations of the departure time of the radio wave;
ordering the base stations to receive the increased power radio wave radiated from the mobile station;
measuring with each base station distances between each base station and the mobile station based on receipt of the increased power radio wave;
and
estimating the location of the mobile station based upon the respective distances measured by the base stations.

5 more elements

Dependencies are inferred from the claim text.

System and method for estimating location of mobile station

Life of this patent

System and method for estimating location of mobile station

Life of this patent

Abstract

Claims27