Patent ID: 6219333
Filing Date: 2001-04-17
Classification: H04L

Abstract:
A method for synchronizing a carrier frequency of an OFDM transmission system, comprising the steps of:selecting one of a coarse mode for correcting an integer part of a carrier frequency offset and a fine mode for correcting a prime part of the carrier frequency offset;calculating a strength of a carrier which is received in each subchannel when the coarse mode is selected;accumulating the calculated strength of the carrier and a strength of a previous carrier delayed for a duration of one symbol for a predetermined period until the accumulated value reaches a predetermined threshold value;correcting the integer part of the carrier frequency offset using the accumulated value;extracting a pilot signal from the carrier when the fine mode is selected;calculating a phase difference between the extracted pilot signal and a previously extracted pilot signal which is delayed for a duration of one symbol; andcorrecting the prime part of the carrier frequency offset within a predetermined frequency by controlling a gain of the calculated phase difference.