Patent ID: 7672277

Claim:
A method for estimating carrier frequency offset in subscriber terminals in TD-SCDMA system, the method comprising: A. determining number of effective base stations with same carrier frequency from which more than one signals are received by a subscriber terminal and main path positions of each signal; B. combining the signals of each base station with same carrier frequency corresponding to the number of effective base stations with same carrier frequency based on the main path positions obtained in step A; C. calculating a rough estimation value of the carrier frequency offset based on combined signal in step B; wherein the determining number of effective base stations with same carrier frequency from which more than one signals are received by a subscriber terminal in step A comprises: A1. calculating peak power value of each signal received by the subscriber terminal, and selecting the peak power values of predefined maximum number of base stations with same carrier frequency from higher to lower; A2. determining the number of effective base stations with same carrier frequency from the signals determined in step A1 by the predefined maximum number of base stations with same carrier frequency are received by the subscriber terminal by comparing the ratio of the highest peak power value from the order in step A1 to the subsequent peak power values with a given threshold; wherein step A2 further comprises: A21. numbering the peak power values ordered from the highest to the lowest and setting a current sequence number as predefined number of the base stations with same carrier frequency; A22. determining whether the highest peak power value and a peak power value corresponding to the current sequence number are greater than the given threshold, if so, setting the number of effective base stations with same carrier frequency from which the signals are received by a subscriber terminal as the value of the current sequence number, otherwise, the current sequence number decreases by one and returns back to step A22.