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公开(公告)号：US12224889B2
公开(公告)日：2025-02-11
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
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.
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公开(公告)号：US11381317B2
公开(公告)日：2022-07-05
申请号：US17420845
申请日：2020-01-06
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Seiji Okamoto , Yoshiaki Kisaka , Masanori Nakamura
IPC: H04B10/2513 , H04B10/61
Abstract: An optical receiving device that divides receive signals obtained by receiving an optical signal using a coherent detection scheme into a plurality of frequency bands, matches timing of the receive signals along a time axis between the frequency bands resulting from the division, performs a combining process of combining the receive signals contained in the plurality of frequency bands, and compensates the receive signals for waveform distortion either before or after the combining process, includes: a first wavelength dispersion compensation unit adapted to compensate the receive signals for waveform distortion in each of the frequency bands resulting from the division; a first nonlinear compensation unit adapted to compensate the receive signals belonging to each of the frequency bands and timed with each other in a time domain for a nonlinear optical effect; and a second wavelength dispersion compensation unit adapted to compensate the receive signals belonging to each of the frequency bands and compensated for the nonlinear optical effect for wavelength dispersion in each of the frequency bands.
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公开(公告)号：US10305675B2
公开(公告)日：2019-05-28
申请号：US15568696
申请日：2017-01-16
Inventor： Yasuharu Onuma , Masahiro Tachibana , Etsushi Yamazaki , Kazuhito Takei , Yuki Yoshida , Masayuki Ikeda , Yoshiaki Kisaka , Masahito Tomizawa
Abstract: An FIR filter convolutes sampled data obtained by sampling a reception signal with tap coefficients. A phase difference detector detects a phase difference between a synchronization timing of a signal waveform estimated from an output signal of the FIR filter and a sampling timing of the output signal. A tap coefficient adjuster adjusts the tap coefficients so as to reduce the phase difference detected by the phase difference detector and causes the sampling timing of the output signal of the FIR filter to track the synchronization timing.
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公开(公告)号：US10171173B2
公开(公告)日：2019-01-01
申请号：US15122582
申请日：2015-03-17
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Seiji Okamoto , Koichi Ishihara , Etsushi Yamazaki , Mitsuteru Yoshida , Tomoyoshi Kataoka , Kazushige Yonenaga , Yoshiaki Kisaka , Masanori Nakamura , Masahito Tomizawa
IPC: H04B10/50 , H04B10/516 , H04B10/2513 , H04L27/34 , H04B10/508 , H04B10/077 , H04B10/2557 , H04L27/36
Abstract: An optical signal transmission apparatus includes a modulation unit which modulates a transmission signal, a training signal sequence generation unit which generates a plurality of signal sequences having power concentrated in a plurality of different frequency bands, at least one of an amplitude and a phase of the plurality of signal sequences being modulated, as a training signal sequence, a signal multiplexing unit which appends the training signal sequence to the transmission signal, and an electro-optical conversion unit which converts a signal sequence obtained by appending the training signal sequence to the transmission signal into an optical signal and transmits the optical signal.
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公开(公告)号：US11671119B2
公开(公告)日：2023-06-06
申请号：US17056719
申请日：2019-05-09
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Seiji Okamoto , Etsushi Yamazaki , Masanori Nakamura , Yoshiaki Kisaka , Masahito Tomizawa
CPC classification number: H03M13/353 , H04L1/0041 , H04L1/203 , H04B10/50
Abstract: A signal processing device includes a distributing unit and a plurality of correcting units with different processing performance, the distributing unit distributes a bit sequence having a first number of bits to the first correcting unit, and a bit sequence having a second number of bits less than the first number of bits to the second correcting unit having lower processing performance than the first correcting unit, the first correcting unit applies error correction processing to the bit sequence having the first number of bits distributed to the first correcting unit, and the second correcting unit applies error correction processing to the bit sequence having the second number of bits distributed to the second correcting unit.
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Patent Agency Ranking
6.发明授权公开(公告)号：US11349572B2
公开(公告)日：2022-05-31
申请号：US17056409
申请日：2019-05-08
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Masanori Nakamura , Seiji Okamoto , Etsushi Yamazaki , Yoshiaki Kisaka
IPC: H04B10/50 , H04B10/69 , H04N19/129 , H04N19/103
Abstract: An optical communication system is provided in which a serial/parallel converting unit outputs bit sequences of sequence groups a number of which is determined by a logarithmic value and a bit sequence of a highest-order sequence group, a converting unit converts the bit sequence of the sequence group input to the converting unit into a bit sequence for which a probability of occurrence of 0 or a probability of occurrence of 1 is a predetermined probability of occurrence, a selecting unit acquires a bit sequence for which the probability of occurrence is converted by a converting unit higher in order than the converting unit for the selecting unit, and selects an order of output of a symbol to other selecting units in the sequence groups higher in order than the selecting unit in accordance with the acquired bit sequence, a multiplication unit multiplies a value representing the symbol selected by a highest-order selecting unit, by a number in accordance with the bit sequence of the highest order sequence group, a transmission unit transmits an optical signal based on a result of the multiplication by the number, an optical receiver includes a reception unit and a demodulation unit, and the reception unit receives the optical signal, and performs demodulation processing.
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7.发明授权公开(公告)号：US11323238B2
公开(公告)日：2022-05-03
申请号：US16972531
申请日：2019-06-06
Inventor： Mitsuteru Yoshida , Yasuyuki Endoh , Katsuichi Oyama , Masayuki Ikeda , Tsutomu Takeya , Etsushi Yamazaki , Yoshiaki Kisaka , Masahito Tomizawa
IPC: H04L7/00 , H04L7/04 , H04L27/227 , H04B10/556 , H04B10/61
Abstract: A frame synchronization apparatus (10) according to this invention includes a multiplication unit (11) configured to multiply a received signal by an inverse complex number of a predetermined synchronization pattern with respect to a predetermined signal point on a complex space diagram for each of a plurality of symbols of the received signal, an addition average unit (12) configured to perform addition averaging of outputs from the multiplication unit for the plurality of symbols of the received signal, and a synchronization determination unit (13) configured to perform coincidence determination of whether an output from the addition average unit (12) falls within a predetermined coincidence determination range of the predetermined signal point, and determine a synchronization state of the frame synchronization based on a result of the coincidence determination. According to this invention, it is possible to provide a frame synchronization apparatus that correctly determines a synchronization state even if an error rate of received symbols is high.
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公开(公告)号：US11316588B2
公开(公告)日：2022-04-26
申请号：US17278627
申请日：2019-08-27
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Kyo Minoguchi , Etsushi Yamazaki , Seiji Okamoto , Yoshiaki Kisaka
IPC: H04B10/2513
Abstract: Provided is a chromatic dispersion compensation method including: dividing a reception signal obtained by receiving an optical signal using a coherent detection scheme into a plurality of frequency bands; adjusting a timing on a time axis of the reception signal for each of the divided frequency bands; performing combination processing for combining the reception signals included in the plurality of frequency bands; performing chromatic dispersion compensation on the reception signal at any timing before or after the combination processing; selecting, before the combination processing, sections in which overlapping parts determined based on lengths of overlap parts are generated; outputting the reception signal for each of the selected sections as a division processing block; and removing the overlap parts from both ends of a processing block generated by combination of the division processing blocks in the combination processing so as to be continuous on a frequency axis.
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公开(公告)号：US10122462B2
公开(公告)日：2018-11-06
申请号：US15126557
申请日：2014-11-19
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Takuya Ohara , Kei Kitamura , Yoshiaki Kisaka , Shigeki Aisawa , Masahiro Suzuki , Etsushi Yamazaki , Tomoyoshi Kataoka , Masahito Tomizawa , Yoshiaki Yamada , Mitsuhiro Teshima , Akira Hirano
Abstract: A transport apparatus includes: a client signal transceiving unit which transceives a client signal; a line signal transceiving unit which performs electric-optic conversion on a line signal to be transmitted, transmits an optical line signal, performs optic-electric conversion on a received line signal, and outputs an electrical line signal; and a plurality of signal processing units which perform signal processing on the client signal to generate the line signal to be transmitted and perform signal processing on the electrical line signal to generate the client signal. Each of the plurality of signal processing units includes a signal transceiving unit which performs transfer of a branched signal obtained by branching a signal to be transmitted and a merged signal obtained by merging received signals with another signal processing unit, and the signal transceiving unit of each of the plurality of signal processing units and the signal transceiving unit of the other signal processing unit are coupled via an inter-chip wiring.
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公开(公告)号：US10038507B2
公开(公告)日：2018-07-31
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 , H04L27/38 , H04B10/516 , H04J14/06 , H04L27/00
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.
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