Patent ID: 7894539

Claim:
A method of estimating integer carrier frequency offset between a transmitter and a receiver, comprising: setting a plurality of subcarrier position hypotheses for a received preamble according to a plurality of ideal subcarrier positions and the maximum amount of integer carrier frequency offset between the transmitter and the receiver; generating a plurality of preamble pattern hypotheses by retrieving the received preamble according to the subcarrier position hypotheses; calculating the correlation between the preamble pattern hypotheses and a plurality of specified preamble patterns; determining to which sector the received preamble belongs according to a correct preamble pattern that is the specified preamble pattern having the highest correlation with the preamble pattern hypotheses; determining a sector number to represent the sector to which the received preamble belongs; obtaining a correct subcarrier position according to the sector to which the received preamble belongs; determining a hypothesis number to represent a verified subcarrier position hypothesis that is the subcarrier position hypothesis corresponding to the preamble pattern hypothesis having the highest correlation with the correct preamble pattern; and estimating the integer carrier frequency offset between the transmitter and the receiver by calculating an offset between the correct subcarrier position and the verified subcarrier position hypothesis, wherein the offset between the correct subcarrier position and the verified subcarrier position hypothesis is calculated based on the difference between the sector number and the hypothesis number.