Patent ID: 8571150

Claim:
A frequency offset compensation apparatus in a receiver for communication with a transmitter, comprising: a first estimation unit configured to estimate a first phase rotation caused by a difference between a carrier frequency of the transmitter and a carrier frequency of the receiver in a first period, by using a first known segment included in a received signal, wherein the received signal includes the first known segment and a second known segment which is longer than the first known segment; a second estimation unit configured to estimate a second phase rotation caused by a difference between a carrier frequency of the transmitter and a carrier frequency of the receiver in a second period, by using the second known segment; a setting unit configured to compare a received power of the received signal to a threshold value, and (i) set a weighting factor for the second phase rotation to a first value if the received power of the received signal is determined to be less than the threshold value, and (ii) set the weighting factor for the second phase rotation to a second value which is smaller than the first value if the received power is determined to be greater than or equal to the threshold value; a synthesis unit configured to calculate an offset compensation value by weighting the first phase rotation and the second phase rotation by applying the weighting factor; and a compensation unit configured to compensate for a frequency offset by using the offset compensation value.