Reception apparatus, phase error estimation method, and phase error correction method

Patent metadata

Field	Value
Publication number	US-2016006557-A1
Application number	US-201414770406-A
Country	US
Kind code	A1
Filing date	Feb 20, 2014
Priority date	Feb 27, 2013
Publication date	Jan 7, 2016
Grant date	—

Abstract

In a phase error corrector, a signal extractor extracts received reference signals from received signals, and an error vector calculator calculates the error vectors of phase errors by comparing the extracted received reference signals with a known reference signal that is to be transmitted. A representative vector calculator divides, according to frequency, the error vectors into two or more groups and calculates representative vectors for the respective groups. A correction value calculator calculates, on the basis of the representative vectors, phase correction values for the respective frequencies. A phase corrector uses the calculated phase correction values to correct the phase errors for the respective frequencies.

First claim

1 . A reception apparatus comprising:
a phase error estimator that estimates a phase error estimation value in a frequency domain; and a phase error corrector that corrects the phase error for the received signal by using the phase error estimation value, wherein the phase error estimator includes that a signal extractor extracts a received reference signal in the frequency domain from a received signal including a specific reference signal; an error vector calculator obtains a plurality of error vectors by comparing the received reference signal in the frequency domain and a transmitted reference signal in the frequency domain corresponding to the specific reference signal in a transmitter; and a correction value calculator obtains, based on the plurality of error vectors, an amount of phase error change and a phase error offset in the frequency domain possessed by the received reference signal and obtains the phase error estimation value in the frequency domain based on the amount of phase error change and the phase error offset.

2 . The reception apparatus according to claim 1 , wherein the phase error estimator further includes that
a representative vector calculator divides the error vectors into not less than two groups, obtains a plurality of representative vectors as a representative value of each group, and the correction value calculator obtains the amount of phase error change and the phase error offset based on the plurality of representative vectors.

3 . A phase error estimation method of a reception apparatus, comprising:
extracting a received reference signal in a frequency domain in a receiver from a received signal including a specific reference signal; obtaining a plurality of error vectors by comparing the received reference signal in the frequency domain and a transmitted reference signal in the frequency domain corresponding to the specific reference signal in a transmitter; dividing the error vectors into not less than two groups, a plurality of representative vectors as a representative value of each group; and obtaining an amount of phase error change and a phase error offset in the frequency domain possessed by the received reference signal based on the plurality of representative vectors, and obtaining a phase error value in the frequency domain based on the amount of phase error change and the phase error offset.

4 . The phase error estimation method according to claim 3 , wherein in the obtaining of the phase error value, the representative vectors are converted from vectors into phases, and when the phases between the representative vectors are discontinuous, a predetermined phase value is added or subtracted to the phases.

5 . The phase error estimation method according to claim 3 , wherein in the obtaining of the representative vectors, the groups are divided according to a magnitude of a frequency of each error vector, and are groups of a predetermined number of error vectors extracted in decreasing order of a magnitude of an amplitude of representative vector.

6 . The phase error estimation method according to claim 3 , wherein in the obtaining of the representative vectors, as the representative value of each group, a mean value is obtained by vector mean of the error vectors.

7 . The phase error estimation method according to claim 6 , wherein in the obtaining of the representative vectors, the mean value is obtained by adding the error vectors.

8 . The phase error estimation method according to claim 6 , wherein in the obtaining of the representative vectors, by using a plurality of error vectors to which a predetermined weight is assigned according to a magnitude of an amplitude of each error vector in the frequency domain, the mean value is obtained by adding the error vectors.

9 . The phase error estimation method according to claim 4 , wherein in the obtaining of the phase error, it is determined that the phases between the representative vectors are discontinuous when an absolute value of a phase difference between two target representative vectors of the representative vectors is not less than π.

10 . The phase error estimation method according to claim 3 , wherein in the obtaining of the phase error, the representative vectors are converted from vectors into phases, and for phases of two target representative vectors of the representative vectors, wrapping subtraction of the phase of a low frequency from the phase of a high frequency is performed so that a calculation result falls within a range of ±π and division by a frequency difference between the two representative vectors is performed.

11 . The phase error estimation method according to claim 3 , wherein in the estimation of the phase error, the representative vectors are converted from vectors into phases, phases of two target representative vectors of the representative vectors are added and gain multiplication by ½ is performed, and when the phases between the representative vectors are discontinuous, wrapping addition of π to a result of the gain multiplication is performed so that a calculation result falls within a range of ±π.

12 . The phase error estimation method according to claim 3 , wherein in the obtaining of the representative vectors, the groups are divided into not less than three groups and a representative value of each group is obtained; and
wherein in the estimation of the phase error, the representative vectors are converted from vectors into phases, unwrapping processing is performed on the phases after the conversion and linear approximation by an LSM is performed.

13 . The reception apparatus according to claim 1 , wherein the signal extractor extracts the received reference signal after rough carrier frequency offset correction and rough symbol synchronization shift correction;
wherein the correction value calculator obtains the phase error estimation value with linear approximation by obtaining the amount of phase error change as a residual symbol synchronization shift and the phase error offset as a residual carrier frequency offset; and
wherein the phase error corrector performs correction of the residual symbol synchronization shift in the frequency domain, converts the received signal in the frequency domain to a time domain, and performs correction of the residual carrier frequency offset on the received signal converted from the frequency domain to the time domain.

14 . The reception apparatus according to claim 1 , wherein the signal extractor extracts the received reference signal after rough carrier frequency offset correction and rough symbol synchronization shift correction;
wherein the correction value calculator obtains the phase error estimation value with linear approximation by obtaining the amount of phase error change as a residual symbol synchronization shift and the phase error offset as a residual carrier frequency offset; and
wherein the phase error corrector converts the received signal in the frequency domain into a time domain, performs correction of the residual carrier frequency offset on the received signal converted from the frequency domain into the time domain, and performs correction of the residual symbol synchronization shift on the received signal converted from the frequency domain into the time domain.

15 . A phase error correction method of a reception apparatus, comprising:
extracting a received reference signal in a frequency domain from a received signal including a specific reference signal after rough carrier frequency offset correction and rough symbol synchronization shift correction in a receiver; obtaining a pluralit

Assignees

• Panasonic Corp

Inventors

• Shirakawa Yoshinori
• Tanaka Koichiro
• Sakamoto Takenori

Classifications

• H04L7/0041 Primary

  Delay of data signal · CPC title

• H04L7/0054

  Detection of the synchronisation error by features other than the received signal transition (by means of signal transition H04L7/033) · CPC title

• H04L7/04

  Speed or phase control by synchronisation signals {(H04L7/0075 takes precedence)} · CPC title

• H04L27/22 Primary

  Demodulator circuits; Receiver circuits · CPC title

• H04L27/2675

  Pilot or known symbols · CPC title