公开(公告)号：US20220303003A1

公开(公告)日：2022-09-22

申请号：US17635275

申请日：2019-09-17

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kengo HORIKOSHI ,  Masanori NAKAMURA ,  Seiji OKAMOTO ,  Hideki NISHIZAWA ,  Etsushi YAMAZAKI

IPC: H04B10/079 ,  H04B10/61 ,  H04B10/2569

Abstract: A signal processing apparatus includes: a coefficient update unit configured to approximate a characteristic of a transmission line of an optical signal by a first tap coefficient vector of which an LO norm is a predetermined value or less; a zeroing unit configured to generate a second tap coefficient vector by replacing, with 0, a tap coefficient of which an absolute value is less than a threshold among tap coefficients of the first tap coefficient vector; and an adaptive filter configured to perform, based on the second tap coefficient vector, adaptive equalization processing on a digital signal corresponding to an optical signal received via the transmission line.

公开(公告)号：US20220140906A1

公开(公告)日：2022-05-05

申请号：US17426817

申请日：2020-01-30

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takashi MITSUI ,  Toshiaki SHITABA ,  Akihiro TANABE ,  Kengo HORIKOSHI ,  Hisao YOSHINAGA

IPC: H04B10/293 ,  H04B10/572

Abstract: An optical transmission system includes: a first optical transmitting unit for transmitting a first optical signal having a first wavelength; a second optical transmitting unit for transmitting a second optical signal having a second wavelength; an output adjustment unit for acquiring the first optical signal and the second optical signal, adjusting signal intensities of the acquired optical signals, and outputting the optical signals; a multiplexer for multiplexing the first optical signal and the second optical signal that have been subjected to signal intensity adjustment and outputting a multiplexed signal; an amplifier for amplifying the multiplexed signal; a first optical receiving unit for receiving the amplified first optical signal; and a second optical receiving unit for receiving the amplified second optical signal. The output adjustment unit adjusts the signal intensities of the first optical signal and the second optical signal such that the signal intensity of the first optical signal received by the first optical receiving unit is larger than or equal to a first predetermined value, and the signal intensity of the second optical signal received by the second optical receiving unit is larger than or equal to a second predetermined value.

公开(公告)号：US20220069921A1

公开(公告)日：2022-03-03

申请号：US17424766

申请日：2020-01-15

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

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

IPC: H04B10/69 ,  H04B10/548 ,  H04B10/67

Abstract: There are provided an optical transmission apparatus that subjects a transmission signal including a plurality of sequences to Hadamard transform to obtain a signal in which a predetermined delay is added to one of the sequences, optically modulates the obtained signal, and transmits the modulated signal, and an optical reception apparatus that demodulates a reception signal received from the optical transmission apparatus by subjecting the reception signal to adaptive equalization processing with a predetermined number of taps. The optical reception apparatus includes: an adaptive equalization processing unit that subjects the reception signal to adaptive equalization processing of wavelength distortion compensation with a number of taps obtained by subtracting a number in accordance with the delay from the predetermined number of taps; a delay compensation unit that subjects the reception signal subjected to the wavelength distortion compensation to delay compensation in accordance with the delay; and an inverse Hadamard transform unit that subjects the reception signal subjected to the delay compensation to inverse Hadamard transform.

公开(公告)号：US20180252614A1

公开(公告)日：2018-09-06

申请号：US15555321

申请日：2016-10-04

Applicant: NTT ELECTRONICS CORPORATION ,  NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Etsushi YAMAZAKI ,  Tomohiro TAKAMUKU ,  Yuki YOSHIDA ,  Mitsuteru YOSHIDA ,  Koki SHIBAHARA ,  Kengo HORIKOSHI ,  Yoshiaki KISAKA

IPC: G01M11/02 ,  H04B10/079 ,  H04B10/2513 ,  H04B3/06 ,  G01M11/00

Abstract: A Fourier-transformer performs Fourier transform on a filter coefficient output from an adaptive equalizer which comprises a finite impulse response filter of N taps (N represents an integer of 2 or more) in a time direction. An eigenvalue sum calculator integrates a frequency-differentiation result of the Fourier-transformed filter coefficient and a complex conjugate of the Fourier-transformed filter coefficient to calculate a matrix, and calculates a sum of two eigenvalues of the matrix. A proportionality factor calculator calculates a proportionality factor for frequency from the sum of the two eigenvalues.

公开(公告)号：US20150372766A1

公开(公告)日：2015-12-24

申请号：US14766635

申请日：2014-02-13

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Mitsuteru YOSHIDA ,  Etsushi YAMAZAKI ,  Seiji OKAMOTO ,  Hiroyuki UZAWA ,  Kengo HORIKOSHI ,  Koichi ISHIHARA ,  Takayuki KOBAYASHI ,  Yoshiaki KISAKA ,  Masahito TOMIZAWA ,  Naoki FUJIWARA ,  Tomoyoshi KATAOKA ,  Kazushige YONENAGA

IPC: H04B10/61 ,  H04B10/2507 ,  H04J14/06 ,  H04B10/516

CPC classification number: H04B10/6165 ,  H04B10/2507 ,  H04B10/516 ,  H04B10/61 ,  H04J14/06 ,  H04L27/38 ,  H04L2027/0067 ,  H04L2027/0095

Abstract: An increase in circuit scale is suppressed and a phase variation caused in a transmission path or the like is compensated for. An optical transmission system includes: a pilot symbol detection unit which detects a plurality of pilot symbols intermittently inserted into a received complex electric field signal that is obtained through coherent detection for a received optical signal; an error signal computation unit which calculates a complex electric field error signal indicating a phase variation at each pilot symbol based on the pilot symbols detected by the pilot symbol detection unit and a predetermined reference symbol; a compensation electric field signal generation unit which estimates a phase variation between the pilot symbols in the received complex electric field signal using filter processing based on the complex electric field error signal calculated by the error signal computation unit; and a phase noise compensation unit which performs phase compensation for the received complex electric field signal based on the phase variation between the pilot symbols estimated by the compensation electric field signal generation unit.

Abstract translation: 抑制电路规模的增加，并且补偿在传输路径等中引起的相位变化。 光传输系统包括：导频符号检测单元，其检测间歇地插入到通过接收的光信号的相干检测获得的接收复电场信号中的多个导频符号; 误差信号计算单元，基于由导频符号检测单元检测的导频符号和预定的参考符号，计算指示每个导频符号的相位变化的复电场误差信号; 补偿电场信号生成单元，其基于由所述误差信号计算单元计算的复电场误差信号，使用滤波处理来估计所述接收复电场信号中的导频符号之间的相位变化; 以及相位噪声补偿单元，其基于由补偿电场信号生成单元估计的导频符号之间的相位变化，对接收到的复数电场信号进行相位补偿。

公开(公告)号：US20240187107A1

公开(公告)日：2024-06-06

申请号：US18283244

申请日：2021-03-24

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kengo HORIKOSHI ,  Etsushi YAMAZAKI ,  Seiji OKAMOTO

IPC: H04B10/61

CPC classification number: H04B10/6165

Abstract: 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.

公开(公告)号：US20240007195A1

公开(公告)日：2024-01-04

申请号：US18039125

申请日：2020-12-14

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kengo HORIKOSHI ,  Seiji OKAMOTO ,  Masanori NAKAMURA

IPC: H04B10/61 ,  H04J14/06

CPC classification number: H04B10/6162 ,  H04J14/06 ,  H04B10/6166

Abstract: An adaptive equalizer includes an updating unit that updates a step size of a vector of a tap coefficient used for controlling an adaptive filter based on a time-series update vector in accordance with a time-series input and output of the adaptive filter that tracks a polarization state of an optical signal received by a coherent optical receiver. The updating unit updates the step size based on a DC gain of the update vector. The updating unit may update the step size for each update vector component based on a DC gain for each update vector component.

公开(公告)号：US20220224415A1

公开(公告)日：2022-07-14

申请号：US17614686

申请日：2019-06-06

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Masanori NAKAMURA ,  Seiji Okamoto ,  Kengo HORIKOSHI ,  Shuto YAMAMOTO ,  Takayuki KOBAYASHI ,  Yoshiaki KISAKA ,  Masahito TOMIZAWA

IPC: H04B10/2513 ,  H04B10/61 ,  H03H17/02

Abstract: An electric digital received signal obtained from a received optical signal is segmented into blocks of a certain length with an overlap of a length determined in advance with an adjacent block. Fourier transformation is performed for each of the blocks. The blocks subjected to the Fourier transformation are stored consecutively in time series, a coefficient determined based on a wavelength dispersion compensation amount according to one of frequency positions and a delay amount according to one of the frequency positions and one of time positions is applied to each of frequency component values included in a plurality of the stored blocks, and the blocks to which the coefficient has been applied and which are obtained by adding up the frequency component values to which the coefficient has been applied for each of the frequency positions are generated. Inverse Fourier transformation is performed on the generated blocks to which the coefficient has been applied. A part of the overlap subjected to the inverse Fourier transformation is removed.

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.