US 8,571,150 B2Granted

Frequency offset compensation apparatus

AssigneeKabushiki Kaisha Toshiba

InventorsSeiichiro Horikawa, Koichiro Ban

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Abstract

According to one embodiment, a frequency offset compensation apparatus includes a first estimation unit, a second estimation unit, a setting unit, a synthesis unit and a compensation unit. The first estimation unit estimates a first rotation. The second estimation unit estimates a second rotation. The setting unit sets a weighting factor for the second rotation to a first value if a received power is less than a threshold value, and sets the weighting factor for the rotation to a second value being smaller than the first value if the received power is not less than the threshold value. The synthesis unit calculates a compensation value. The compensation unit compensates for a frequency offset.

Claims8

Dependent claims

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.

3 more elements

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 determine whether header information of a physical layer of the received signal indicates a state of relatively high-speed data communication or a state relatively low-speed data communication, and (i) set a weighting factor for the second phase rotation to a first value if the header information is determined to indicate the state of relatively low-speed data communication between the transmitter and the receiver, and (ii) set the weighting factor for the second phase rotation to a second value which is smaller than the first value if the header information is determined to indicate a state of relatively high-speed data communication between the transmitter and the receiver, wherein the high-speed data communication has a communication speed that is faster than a communication speed in the low-speed data communication;
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.

3 more elements

Dependencies are inferred from the claim text.