Phase compensation device, phase compensation method and communication apparatus

Patent metadata

Field	Value
Publication number	US-10419127-B2
Application number	US-201716072420-A
Country	US
Kind code	B2
Filing date	Apr 13, 2017
Priority date	Jun 17, 2016
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

A symbol phase difference compensating portion (6) calculates a first phase difference which is a phase difference between a known pattern extracted from a received signal and a true value of the known pattern and performs phase compensation for the received signal based on the first phase difference. A tentative determination portion (12) tentatively determines an output signal of the symbol phase difference compensating portion (6) to acquire an estimated value of a phase. A first phase difference acquiring portion (13) acquires a second phase difference which is a phase difference between a phase of the output signal and the estimated value of the phase acquired by the tentative determination portion (12). A first phase difference compensating portion (14) performs phase compensation for the output signal based on the second phase difference.

First claim

The invention claimed is:

1. A phase compensation device comprising:
a symbol phase difference compensating portion calculating a first phase difference which is a phase difference between a known pattern extracted from a received signal and a true value of the known pattern and performing phase compensation for the received signal based on the first phase difference;
a tentative determination portion tentatively determining an output signal of the symbol phase difference compensating portion to acquire an estimated value of a phase;
a first phase difference acquiring portion acquiring a second phase difference which is a phase difference between a phase of the output signal and the estimated value of the phase acquired by the tentative determination portion; and
a first phase difference compensating portion performing phase compensation for the output signal based on the second phase difference.

2. The phase compensation device according to claim 1 , wherein the symbol phase difference compensating portion includes:
a known pattern extracting portion extracting the known pattern inserted in the received signal;
a reference signal storing portion storing the true value of known pattern as a reference signal;
a second phase difference acquiring portion acquiring the first phase difference which is a phase difference between the known pattern extracted by the known pattern extracting portion and the reference signal; and
a second phase difference compensating portion performing phase compensation for the received signal based on the first phase difference.

3. The phase compensation device according to claim 1 , further comprising a rotational folding portion rotating and folding a signal existing in other quadrant into any one of the first to fourth quadrants on a constellation for the output signal of the symbol phase difference compensating portion,
wherein the tentative determination portion and the first phase difference acquiring portion perform processing for the output signal folded by the rotational folding portion.

4. The phase compensation device according to claim 1 , wherein the tentative determination portion sets an estimated value of a phase for each of a plurality of threshold regions on a constellation, and determines an estimated value of a phase corresponding to a threshold region in which the output signal is included,
the plurality of threshold regions include a first threshold region and a second threshold region,
an amplitude of a signal to which the second threshold region corresponds is larger than an amplitude of a signal to which the first threshold region corresponds, and
the second threshold region extends in a phase rotation direction in comparison with the first threshold region.

5. The phase compensation device according to claim 1 , wherein the first phase difference acquiring portion calculates a complex conjugate of the output signal, multiplies the complex conjugate by a signal outputted by the tentative determination portion to calculate an electric field information signal and acquires the second phase difference from the electric field information signal.

6. The phase compensation device according to claim 1 , wherein the first phase difference acquiring portion calculates a complex conjugate of the output signal, multiplies the complex conjugate by a signal outputted by the tentative determination portion to calculate an electric field information signal, calculates a rotation angle from the electric field information signal and acquires the second phase difference from the rotation angle.

7. A communication apparatus comprising:
photoelectric conversion portion converting an optical signal to an analog electrical signal;
an AD conversion portion converting the analog electrical signal to the received signal which is a digital electrical signal; and
the phase compensation device according to claim 1 performing phase compensation for the received signal.

8. A phase compensation method performed by a phase compensation device comprising:
calculating a first phase difference between a known pattern extracted from a received signal and a true value of the known pattern and performing phase compensation for the received signal based on the first phase difference to acquire an output signal;
tentatively determining the output signal to acquire an estimated value of a phase;
acquiring a second phase difference between a phase of the output signal and the estimated value of the phase; and
performing phase compensation for the output signal based on the second phase difference.

Assignees

• Ntt Electronics Corp
• Nippon Telegraph & Telephone

Inventors

• Yamazaki Etsushi
• Nouchi Hiroyukl
• Onuma Yasuharu
• TAKAMUKU Tomohiro
• Oyama Katsuichi
• Takei Kazuhito
• Tomizawa Masahito
• Kisaka Yoshiaki
• Yoshida Mltsuteru
• Nakamura Masanori

Classifications

• H04L27/38

  Demodulator circuits; Receiver circuits · CPC title

• H04L27/01

  Equalisers {(baseband equalizers at the transmitter end H04L25/03343; in analogue transmission systems H04B3/04, H04B7/005)} · CPC title

• H04B10/61

  Coherent receivers · CPC title

• H04B10/6165

  Estimation of the phase of the received optical signal, phase error estimation or phase error correction · CPC title

• H04L2027/0024

  at the receiver end · CPC title