FREQUENCY OFFSET ESTIMATION APPARATUS, RECEIVING APPARATUS, FREQUENCY OFFSET ESTIMATION METHOD AND PROGRAM
A frequency offset estimation device includes a correlation processing unit that obtains a correlation pattern that is a waveform pattern indicating a correlation between a reception signal spectrum and a detection pattern based on a power spectrum of the reception signal or the reception signal spectrum indicating an amplitude spectrum based on the power spectrum and the detection pattern that is a predetermined waveform pattern, and an estimation unit that estimates a frequency offset amount based on a peak position of the correlation pattern obtained by the correlation processing unit.
1 . A frequency offset estimation device comprising:
a correlation processor that obtains a correlation pattern that is a waveform pattern indicating a correlation between a reception signal spectrum and a detection pattern based on a power spectrum of the reception signal or the reception signal spectrum indicating an amplitude spectrum based on the power spectrum and the detection pattern that is a predetermined waveform pattern; and
an estimator that estimates a frequency offset amount based on a peak position of the correlation pattern obtained by the correlation processing unit.
2 . The frequency offset estimation device according to claim 1 , wherein the detection pattern is a waveform pattern for detecting a spectrum edge of the reception signal in a case where the reception signal is a single carrier signal, and a waveform pattern for detecting at least one of a spectrum edge of the reception signal and a spectrum gap between subcarriers of the reception signal when the reception signal is a multi-carrier signal.
3 . The frequency offset estimation device according to claim 1 , wherein the detection pattern is a waveform pattern generated using second differentiation of an expected value of the reception signal spectrum or a rectangular pattern approximate to the waveform pattern.
4 . The frequency offset estimation device according to claim 2 , wherein the detection pattern for detecting the spectrum edge is a waveform pattern generated based on a Hermitian wavelet based on a first derivative of a Gaussian function, and
the detection pattern for detecting the spectrum gap is a waveform pattern generated based on a Hermitian wavelet based on a second derivative of a Gaussian function.
5 . The frequency offset estimation device according to claim 4 , wherein the detection pattern is a rectangular waveform pattern approximate to a waveform pattern generated based on the Hermitian wavelet.
6 . A reception device of a coherent optical communication system, the device comprising:
a correlation processor that obtains a correlation pattern indicating a correlation between a reception signal spectrum and a detection pattern based on a power spectrum of the reception signal or the reception signal spectrum indicating an amplitude spectrum based on the power spectrum and the detection pattern that is a predetermined waveform pattern;
an estimator that estimates a frequency offset amount based on a peak position of the correlation pattern obtained by the correlation processor; and
a compensator that compensates for a frequency offset based on the frequency offset amount estimated by the estimator.
7 . A frequency offset estimation method comprising:
a correlation processing step of obtaining, by a computer, a correlation pattern indicating a correlation between a reception signal spectrum and a detection pattern based on a power spectrum of the reception signal or the reception signal spectrum indicating an amplitude spectrum based on the power spectrum and the detection pattern that is a predetermined waveform pattern; and
an estimation step of estimating, by the computer, a frequency offset amount based on a peak position of the correlation pattern obtained by the correlation processing step.
8 . A program for causing a computer to function as the frequency offset estimation device according to claim 1 .