公开(公告)号：US20230291482A1

公开(公告)日：2023-09-14

申请号：US18012051

申请日：2020-07-30

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Shuto YAMAMOTO ,  Masanori NAKAMURA ,  Hiroki TANIGUCHI ,  Yoshiaki KISAKA

IPC: H04B10/58 ,  H04B10/2513

CPC classification number: H04B10/58 ,  H04B10/2513

Abstract: An optical transmission system is an optical transmission system for transmitting a signal from an optical transmitter to an optical receiver via at least a transmission line among one or more optical nodes and the transmission line, wherein the optical transmitter includes a digital filter that compensates for, between ripple components that are micro-fluctuating components in a frequency region representing a transmission characteristic of the signal in the optical transmitter and the optical receiver and non-ripple components of the transmission characteristic, at least the ripple components of the transmission characteristic, and at least one of the optical node and the optical transmitter includes an optical filter that compensates for the non-ripple components of the transmission characteristic.

公开(公告)号：US20230261759A1

公开(公告)日：2023-08-17

申请号：US18017890

申请日：2020-08-03

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Shuto YAMAMOTO ,  Masanori NAKAMURA ,  Hiroki TANIGUCHI ,  Yoshiaki KISAKA

IPC: H04B10/69

CPC classification number: H04B10/69

Abstract: According to an aspect of the present invention, there is provided an optical signal demodulator including an optical reception unit, an AD conversion unit, a digital signal processing unit, and a signal determination unit, in which the signal determination unit includes: a spectrum shaping filter processing unit that receives a reception signal sequence of the digital signal from the digital signal processing unit and outputs a value obtained by performing a convolution operation on the reception signal sequence which is received; a transmission line simulation filter processing unit that outputs a value obtained by performing a convolution operation on a candidate signal sequence which is determined based on a symbol transition of the reception signal; an error information acquisition unit that acquires error information between the value output from the spectrum shaping filter processing unit and the value output from the transmission line simulation filter processing unit; and a bit determination unit that determines a value of a bit included in the symbol transmitted by a transmission unit based on the error information acquired by the error information acquisition unit.

公开(公告)号：US20230071063A1

公开(公告)日：2023-03-09

申请号：US17785833

申请日：2019-12-18

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Shuto YAMAMOTO ,  Masanori NAKAMURA ,  Hiroki TANIGUCHI ,  Yoshiaki KISAKA

IPC: H04B10/516 ,  H04B10/61

Abstract: An optical transmitter generates symbols for transmission by applying a predetermined coding method to each of m-valued transmission symbols generated from transmission data, generates signal light by performing optical modulation on the basis of the symbols for transmission, and transmits the signal light. An optical receiver generates a series of digital signals from the received signal light, detects coded symbols by applying predetermined digital signal processing to the series of digital signals, decodes the m-valued transmission symbols from the detected coded symbols, and restores the transmission data from the decoded m-valued transmission symbols. An operation based on the predetermined coding method performs nonlinear coding that generates the coded symbols by generating m-valued intermediate symbols from the m-valued transmission symbols, the nonlinear coding restricting transitions between series of the coded symbols in time series by assigning bit information to a state transition between coded symbols adjacent in time series and making a number of states that each of the coded symbols can take on greater than a number of states of the m-valued transmission symbols.

公开(公告)号：US20230361881A1

公开(公告)日：2023-11-09

申请号：US18021869

申请日：2020-08-24

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Hiroki TANIGUCHI ,  Masanori NAKAMURA ,  Shuto YAMAMOTO ,  Yoshiaki KISAKA

IPC: H04B10/60 ,  H04B10/516

CPC classification number: H04B10/60 ,  H04B10/516

Abstract: The symbol determination device generates the plurality of estimated reception symbol sequences on the basis of the estimated transfer function of the transmission line represented by the tap gain value applied to each tap of the nonlinear filter including the plurality of taps and the plurality of candidate symbol sequences, determines the transmission symbol by the maximum likelihood sequence estimation on the basis of the determination target reception symbol sequence obtained from the reception signal sequence and each of the plurality of estimated reception symbol sequences, identifies the estimated transmission symbol corresponding to the determination target reception symbol sequence, calculates the new tap gain values on the basis of the determination target reception symbol sequence and the identified estimated transmission symbol sequence, updates the estimated transfer function by applying the calculated tap gain values to the taps of the transmission line estimation unit, and selects the tap to be used on the basis of the magnitude of the calculated new tap gain value and the predetermined tap gain threshold value.

公开(公告)号：US20220224575A1

公开(公告)日：2022-07-14

申请号：US17594926

申请日：2020-05-08

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Hiroki TANIGUCHI ,  Masanori NAKAMURA ,  Shuto YAMAMOTO ,  Akira MASUDA ,  Yoshiaki KISAKA

IPC: H04L27/01

Abstract: A device generates a symbol sequence by performing adaptive equalization by an estimation inverse transfer function of a transmission line on a reception signal sequence extracted from the transmission line, and performing provisional determination on the symbol sequence generated; generates a plurality of the symbol sequences indicating transmission line states in a range of a provisional determination symbol provisionally determined and nearby symbols of the provisional determination symbol; generates, based on the plurality of the symbol sequences indicating the transmission line states generated and an estimation transfer function of the transmission line, an estimation reception symbol sequence for each of the transmission line states; calculates a metric between the symbol sequence obtained from the reception signal sequence and each of a plurality of the estimation reception symbol sequences; selects a most likelihood estimation reception symbol sequence of the plurality of the estimation reception symbol sequences, based on the calculated metric, the provisional determination symbol, and the nearby symbols of the provisional determination symbol; and determines a transmission symbol sequence.

公开(公告)号：US20210367671A1

公开(公告)日：2021-11-25

申请号：US17291228

申请日：2019-11-06

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Shuto YAMAMOTO ,  Akira MASUDA ,  Hiroki TANIGUCHI ,  Yoshiaki KISAKA

IPC: H04B10/2507 ,  H04B10/516 ,  H03M13/41 ,  H04B10/61 ,  H04L25/49

Abstract: Provided is an optical transmission system that includes an optical transmitter, and an optical receiver. The optical transmitter includes: a signal coding unit configured to perform nonlinear trellis coding, which corresponds to nonlinear calculation, on a symbol sequence; and a modulator configured to modulate the symbol sequence subjected to the nonlinear trellis coding by the signal coding unit, and transmit the modulated symbol sequence to the optical receiver. The optical receiver includes: a light receiving unit configured to receive an optical signal transmitted from the optical transmitter, and convert the received optical signal into an electrical signal; and a digital signal processing unit configured to perform digital signal processing on the electrical signal to reconstruct the symbol sequence.

公开(公告)号：US20210367670A1

公开(公告)日：2021-11-25

申请号：US17291170

申请日：2019-11-07

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Shuto YAMAMOTO ,  Seiji OKAMOTO ,  Akira MASUDA ,  Hiroki TANIGUCHI ,  Yoshiaki KISAKA

IPC: H04B10/2507 ,  H04B10/516 ,  H03M13/41 ,  H04B10/61 ,  H04L25/49

Abstract: An optical transmission system including an optical transmitter and an optical receiver, wherein the optical transmitter includes a signal coding unit that performs non-linear block coding on an M (M is an integer greater than or equal to 1)-value symbol sequence or a bit sequence input as data information to generate an L (L is an integer greater than or equal to 2, L>M)-value symbol sequence that corresponds to the M-value symbol sequence or the bit sequence in one-to-one correspondence, a digital-to-analog conversion unit that converts the generated L-value symbol sequence to an analog signal, and a modulator that generates an optical modulation signal by performing modulation based on the analog signal, and the optical receiver includes a light receiving unit that receives the optical modulation signal transmitted from the optical transmitter and converts the optical modulation signal to an electrical signal, and a signal decoding unit that restores the M-value symbol sequence or the bit sequence by performing processing that is the reverse of processing performed by the signal coding unit, on the electrical signal.