Patent ID: 6526039
Filing Date: 2003-02-25
Classification: H04B,H04W

Abstract:
A method for estimating a relative timing of a plurality of base stations in an asynchronous mobile communications system, comprising the steps of:receiving at a first mobile station a first downlink signal transmitted by a first one of said base stations and a second downlink signal transmitted by a second one of said base stations; transmitting an uplink signal from the first mobile station to the first and second base stations; and calculating an estimated relative time difference between the time base of said first base station and the time base of said second base station using receive times at the first and second base stations of said uplink signal, transmit times of the first downlink signal and the second downlink signal, and a time difference at the first mobile station between a receive time of the second downlink signal and the transmit time of said uplink signal, wherein the receive times of the uplink signal and the transmit times of the first and second downlink signals are in the time base of the base station transmitting or receiving the respective signal, said calculation accounting for propagation delays between said first mobile station and said first and second base stations.