公开(公告)号：US20200052792A1

公开(公告)日：2020-02-13

申请号：US16340658

申请日：2017-10-16

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Shuto YAMAMOTO ,  Akira MASUDA ,  Yoshiaki SONE ,  Mitsunori FUKUTOKU

IPC: H04B10/54 ,  H04J14/02

Abstract: An encoding device includes an encoding unit, DA conveners, light sources, intensity modulators, and wavelength multiplexers. The encoding unit adds (NM/2) to an encoded signal having a negative minimum value in a range of the encoded signal among encoded signals of N channels of (NM+1) values obtained by calculating an inner product of a Hadamard matrix of N rows and N columns and a matrix having elements of N intensity signals of (M+1) values. The DA converters of the channels convert the encoded signals of the channels from digital signals into electrical analog signals. The light sources output light of wavelengths for use in the channels. The light intensity modulators of the channels intensity-modulate the light output from the light sources with the encoded signals converted into the electrical analog signals by the DA converters. The wavelength multiplexer outputs a wavelength-multiplexed signal obtained by wavelength-multiplexing the light intensity-modulated by the light intensity modulators.

公开(公告)号：US20200244369A1

公开(公告)日：2020-07-30

申请号：US16842117

申请日：2020-04-07

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Shuto YAMAMOTO ,  Akira MASUDA ,  Yoshiaki SONE ,  Mitsunori FUKUTOKU

IPC: H04B10/54 ,  H04J14/02

Abstract: An encoding device includes an encoding unit, DA converters, light sources, intensity modulators, and wavelength multiplexers. The encoding unit adds (NM/2) to an encoded signal having a negative minimum value in a range of the encoded signal among encoded signals of N channels of (NM+1) values obtained by calculating an inner product of a Hadamard matrix of N rows and N columns and a matrix having elements of N intensity signals of (M+1) values. The DA converters of the channels convert the encoded signals of the channels from digital signals into electrical analog signals. The light sources output light of wavelengths for use in the channels. The light intensity modulators of the channels intensity-modulate the light output from the light sources with the encoded signals converted into the electrical analog signals by the DA converters. The wavelength multiplexer outputs a wavelength-multiplexed signal obtained by wavelength-multiplexing the light intensity-modulated by the light intensity modulators.

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.

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：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：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.