公开(公告)号：US20220158731A1

公开(公告)日：2022-05-19

申请号：US17425994

申请日：2020-01-15

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kengo HORIKOSHI ,  Masanori NAKAMURA ,  Yoshiaki KISAKA ,  Seiji OKAMOTO ,  Fukutaro HAMAOKA

IPC: H04B10/2507

Abstract: A wavelength dispersion amount estimation apparatus includes a correlation signal generation unit configured to generate, from a receive signal, a first signal including a main signal of the receive signal and a second signal, which includes an image signal corresponding to the main signal, with a shift by a baud rate of the receive signal relative to the first signal in a frequency domain, a correlation calculation unit configured to calculate a cross correlation of the first signal and the second signal, and a dispersion amount calculation unit configured to calculate a wavelength dispersion amount, based on a position of a peak of the cross correlation.

公开(公告)号：US20210218471A1

公开(公告)日：2021-07-15

申请号：US17055045

申请日：2019-05-08

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Seiji OKAMOTO ,  Masanori NAKAMURA ,  Kengo HORIKOSHI

IPC: H04B10/2513 ,  H04B10/079

Abstract: A reception apparatus includes a dispersion compensation unit configured to acquire an electrical signal resulting from conversion of an optical signal and perform, on the electrical signal, dispersion compensation with a predetermined compensation amount, a clip rate measurement unit configured to measure a clip rate for the electrical signal subjected to the dispersion compensation, and a control unit configured to detect the compensation amount that minimizes the clip rate.

公开(公告)号：US20210028857A1

公开(公告)日：2021-01-28

申请号：US16979662

申请日：2019-03-01

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Fumikazu INUZUKA ,  Shokei KOBAYASHI ,  Akira HIRANO ,  Wataru KAWAKAMI ,  Tetsuro INUI ,  Seiki KUWABARA ,  Kei KITAMURA ,  Takafumi TANAKA ,  Takuya ODA ,  Hideki NISHIZAWA ,  Seiji OKAMOTO

IPC: H04B10/079 ,  H04B10/077 ,  H04B10/272 ,  H04B10/25 ,  H04B10/516

Abstract: There is provided an optical transmission system in which a plurality of optical transmission and reception apparatuses perform 1-to-N transmission and reception of optical signals (N is an integer equal to or greater than 1), the optical transmission system being configured to select a communication condition that includes at least a modulation scheme or a baud rate and is a communication condition when each of the optical transmission and reception apparatuses performs transmission and reception in accordance with a transmission line condition that is between any one first optical transmission and reception apparatus and each of second optical transmission and reception apparatuses, which are N grounds, other than the first optical transmission and reception apparatus.

公开(公告)号：US20200028586A1

公开(公告)日：2020-01-23

申请号：US16497464

申请日：2018-03-26

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Seiji OKAMOTO ,  Yoshiaki KISAKA ,  Kengo HORIKOSHI ,  Mitsuteru YOSHIDA ,  Masahiro SUZUKI

IPC: H04B10/079 ,  H04J14/06

Abstract: A signal-to-noise ratio (SNR) estimation method includes an optical signal transmission step of inserting at least one pair of signal sequences into transmission data and transmitting the transmission data into which the at least one pair of signal sequences is inserted, a signal sequence extraction step of extracting the at least one pair of signal sequences from a received signal obtained by receiving the transmitted transmission data, an inner product calculation step of calculating an inner product value of the extracted at least one pair of signal sequences, a reception power calculation step of calculating reception power of the extracted at least one pair of signal sequences, and an SNR calculation step of calculating an SNR of the at least one pair of signal sequences on the basis of the calculated inner product value and the calculated reception power.

公开(公告)号：US20250055573A1

公开(公告)日：2025-02-13

申请号：US18717521

申请日：2021-12-24

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kyo MINOGUCHI ,  Etsushi YAMAZAKI ,  Yoshiaki KISAKA ,  Kengo HORIKOSHI ,  Seiji OKAMOTO ,  Masanori NAKAMURA

IPC: H04B10/61 ,  H04B10/294

Abstract: A gain adjustment method in an optical transmission system that performs communication by a digital coherent system including an optical transmission device and an optical reception device includes converting an optical signal transmitted from the optical transmission device into an electrical signal, converting the electrical signal from an analog signal to a digital signal, performing first signal processing on the digital signal, performing adaptive equalization processing on the digital signal subjected to the first signal processing using a digital filter, correcting an amplitude of an output signal of the digital filter based on information of the amplitude and a phase of the output signal of the digital filter and the amplitude of a known transmission signal, and performing second signal processing on the output signal of the digital filter whose amplitude has been corrected.

公开(公告)号：US20210218476A1

公开(公告)日：2021-07-15

申请号：US17272790

申请日：2019-08-27

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Akira MASUDA ,  Seiji OKAMOTO ,  Shuto YAMAMOTO ,  Fukutaro HAMAOKA ,  Masanori NAKAMURA ,  Asuka MATSUSHITA ,  Yoshiaki KISAKA

IPC: H04B10/61 ,  H04J14/06 ,  H04B10/079

Abstract: A digital coherent receiver includes: an adaptive equalizer configured to execute, using a first tap coefficient, adaptive equalization processing on a digital signal that corresponds to a signal; a first coefficient updating unit configured to update the first tap coefficient based on the digital signal on which the adaptive equalization processing has not been executed, the digital signal on which the adaptive equalization processing has been executed, and a first step size; a second coefficient updating unit configured to update a second tap coefficient based on the digital signal on which the adaptive equalization processing has not been executed, the digital signal on which the adaptive equalization processing has been executed, and a second step size; and a control unit configured to detect a fluctuation speed of a state of polarization of the digital signal based on the second tap coefficient, and change the first tap coefficient to the updated second tap coefficient if it is determined that the fluctuation speed is higher than or equal to a speed threshold.

公开(公告)号：US20210013963A1

公开(公告)日：2021-01-14

申请号：US16968741

申请日：2019-02-13

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Seiki KUWABARA ,  Wataru KAWAKAMI ,  Hideki NISHIZAWA ,  Seiji OKAMOTO ,  Akira HIRANO ,  Shokei KOBAYASHI ,  Tetsuro INUI ,  Takuya ODA ,  Fumikazu INUZUKA ,  Takafumi TANAKA

IPC: H04B10/079

Abstract: A state estimating device includes a pre-processing unit and an estimating unit. The pre-processing unit acquires data representing at one or more of a phase of a signal transmitted from a transmission unit of a transmission device and received at a reception unit of another transmission device via a transmission path, a reception strength, a reception quality, a voltage after conversion into an electric signal, and a signal processing parameter used in reception processing, and processes the acquired data into feature data to be used for state estimation. The estimating unit estimates a state of the transmission path, an abnormal state of the transmission unit, or an abnormal state of the reception unit, on the basis of the feature data.

公开(公告)号：US20200052793A1

公开(公告)日：2020-02-13

申请号：US16342909

申请日：2017-10-25

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Fukutaro HAMAOKA ,  Seiji OKAMOTO ,  Masanori NAKAMURA ,  Kengo HORIKOSHI ,  Yoshiaki KISAKA

IPC: H04B10/61 ,  H04B3/06 ,  H04L27/01

Abstract: An optical receiver that demodulates an optical modulation signal into a baseband signal, which is an electrical signal, and decodes a received symbol acquired by converting the baseband signal. The optical receiver includes: an analog-to-digital converter that converts the baseband signal into a digital signal of which the number of samples per received symbol is M/N (samples/symbol), M and N being positive integers, M/N being not an integer, and “M >N” being satisfied; and an adaptive equalization processing unit that executes an equalization operation set in advance to output the received symbol on the basis of the digital signal of which the number of samples per received symbol is M/N (samples/symbol) and a predetermined tap coefficient digital signal equalization tap coefficients used for equalization of a signal, the coefficient being updated in any sampling period.

公开(公告)号：US20150341138A1

公开(公告)日：2015-11-26

申请号：US14759329

申请日：2014-01-15

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Koichi ISHIHARA ,  Masato MIZOGUCHI ,  Tomoki MURAKAMI ,  Tomoyoshi KATAOKA ,  Yoshiaki KISAKA ,  Tadao NAKAGAWA ,  Etsushi YAMAZAKI ,  Seiji OKAMOTO ,  Kengo HORIKOSHI ,  Masahito TOMIZAWA ,  Riichi KUDO

IPC: H04J14/08 ,  H04J3/14 ,  H04B10/61 ,  H04B10/077

CPC classification number: H04J14/08 ,  H04B10/0775 ,  H04B10/2513 ,  H04B10/25133 ,  H04B10/516 ,  H04B10/61 ,  H04B10/6161 ,  H04B10/697 ,  H04B2210/072 ,  H04J3/14

Abstract: The estimation of an amount of chromatic dispersion using a training signal sequence is possible. A transmission method includes: a training signal sequence generation step of generating, as training signal sequences, a plurality of signal sequences having power concentrated in a plurality of frequency bands, the power concentrated at different frequency bands; a training signal sequence selection step of selecting at least one training signal sequence from among the plurality of training signal sequences generated in the training signal sequence generation step, a signal multiplexing step of generating a signal sequence obtained by time-division multiplexing the training signal sequence selected in the training signal sequence selection step with a transmission data sequence, and an electrical-to-optical conversion step of transmitting the signal sequence generated in the signal multiplexing step as an optical signal.

Abstract translation: 使用训练信号序列的色散量的估计是可能的。 发送方法包括：训练信号序列生成步骤，将集中在多个频带的功率的多个信号序列作为训练信号序列生成，集中在不同频带的功率; 训练信号序列选择步骤，从在所述训练信号序列生成步骤中生成的所述多个训练信号序列中选择至少一个训练信号序列，生成通过对所述训练信号序列进行时分复用而获得的信号序列的信号复用步骤 在发送数据序列的训练信号序列选择步骤中选择的电 - 光转换步骤，将在信号复用步骤中生成的信号序列作为光信号进行发送。

公开(公告)号：US20230421420A1

公开(公告)日：2023-12-28

申请号：US18038194

申请日：2020-11-25

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Etsushi YAMAZAKI ,  Seiji OKAMOTO ,  Masanori NAKAMURA ,  Kengo HORIKOSHI ,  Takeo SASAI ,  Yoshiaki KISAKA

IPC: H04L27/01 ,  H04L25/03

CPC classification number: H04L27/01 ,  H04L25/03057

Abstract: An aspect of the present invention is an adaptive equalization filter for an optical transmission system, including: a main signal filter; and a coefficient computation unit that updates the filter coefficient of the main signal filter. The pre-stage filter and the post-stage filter receive a sample of the main signal as an input. The pre-stage coefficient computation unit obtains the filter coefficient of the pre-stage filter by feedback control using the gradient method. The post-stage coefficient computation unit obtains the filter coefficient of the post-stage filter by feedforward control. The convolution computation unit obtains the filter coefficient of the main signal filter by convolution computation of the filter coefficient of the pre-stage filter obtained by the pre-stage coefficient computation unit and the filter coefficient of the post-stage filter obtained by the post-stage coefficient computation unit.