公开(公告)号：US20240080045A1

公开(公告)日：2024-03-07

申请号：US18271134

申请日：2021-01-08

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takeshi KAKIZAKI ,  Masanori NAKAMURA ,  Fukutaro HAMAOKA

IPC: H03M13/11 ,  H03M13/29

CPC classification number: H03M13/1125 ,  H03M13/2978

Abstract: There is provided an encoding circuit used for coherent digital signal processing, including: a serial-parallel circuit that divides input data into a plurality of pieces of divided data by serial-parallel conversion; a plurality of encoders that adds an error correction code to the divided data and encodes the divided data; and a bit conversion circuit that converts a bit sequence in order to make an amount of noise generated by a communication channel non-uniform among the plurality of pieces of divided data encoded by each of the plurality of encoders.

公开(公告)号：US20230097193A1

公开(公告)日：2023-03-30

申请号：US17766994

申请日：2019-10-09

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Masanori NAKAMURA ,  Shuto YAMAMOTO ,  Asuka MATSUSHITA ,  Fukutaro HAMAOKA ,  Yoshiaki KISAKA

IPC: H04B10/079 ,  H04B17/15 ,  H04B17/336

Abstract: A tentative decision is made for symbols on the basis of a received signal and a decision threshold, and a tentative decision signal including a sequence of the symbols is output. A scale value indicating a rate of increase or reduction of the received signal or a threshold change rate indicating a degree of change in the decision threshold is updated so that an appearance frequency of each of symbols included in the tentative decision signal matches an appearance frequency of each of symbols in a reference signal obtained by modulating a transmitted signal with a modulation method used in transmission which is shared between a transmitting side and a receiving side, and an SN ratio is calculated using the scale value or the threshold change rate when a degree of agreement between the appearance frequencies is within a predetermined permissible range. When the scale value is updated, a tentative decision is made for the symbols on the basis of the received signal increased or reduced by the updated scale value and the decision threshold, and when the threshold change rate is updated, the tentative decision for the symbols is made on the basis of the received signal and the decision threshold to which the updated threshold change rate is applied.

公开(公告)号：US20220029707A1

公开(公告)日：2022-01-27

申请号：US17311928

申请日：2019-12-04

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Masanori NAKAMURA ,  Fukutaro HAMAOKA ,  Hiroshi YAMAZAKI ,  Munehiko NAGATANI ,  Takayuki KOBAYASHI ,  Yutaka MIYAMOTO

IPC: H04B10/58 ,  H04B10/69

Abstract: An optical transmission system includes an optical transmitter and an optical receiver. The optical transmitter includes a low speed signal generation unit configured to generate, based on an input signal of a transmission data sequence and a signal obtained by cyclically shifting a spectrum of the input signal, a plurality of low speed signals, a high speed signal generation unit configured to digital-to-analog convert and synthesize the plurality of low speed signals to generate a high speed signal, and an optical modulation unit configured to transmit an optical signal obtained by modulation of the high speed signal to a transmission path. The optical receiver includes a reception unit configured to receive the optical signal from the transmission path and output the high speed signal obtained from the optical signal that is received, an optical-receiver-side high speed signal compensation unit configured to compensate, based on the high speed signal output by the reception unit and a signal obtained by cyclically shifting a spectrum of the high speed signal, for the high speed signal, and a reception data decoding unit configured to decode the high speed signal compensated by the optical-receiver-side high speed signal compensation unit to restore binary information included in the optical signal transmitted by the optical transmitter.

公开(公告)号：US20220416890A1

公开(公告)日：2022-12-29

申请号：US17782957

申请日：2019-12-16

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takeo SASAI ,  Fukutaro HAMAOKA ,  Masanori NAKAMURA ,  Seiji OKAMOTO

IPC: H04B10/2543 ,  H04B10/61

Abstract: An optical reception device includes a coefficient update section which optimizes a dispersion coefficient used in compensation of wavelength dispersion of a received signal obtained by receiving an optical signal according to a coherent detection method and a phase rotation amount used in compensation of a nonlinear optical effect of the received signal, and a transmission characteristic estimation section which estimates a transmission characteristic of a transmission line by using the optimized dispersion coefficient and the optimized phase rotation amount.

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：US20210384983A1

公开(公告)日：2021-12-09

申请号：US17265823

申请日：2019-07-02

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

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

IPC: H04B10/516 ,  H04B10/61 ,  H04B10/69 ,  H04L27/36 ,  H04L27/38

Abstract: There is provided a communication system, wherein: an optical transmission apparatus has: a first storage unit that stores amplitude distribution information, which is information representing a distribution of occurrence probabilities of symbols of an optical signal, in association with a modulation rate of an optical signal; a control unit that selects the modulation rate based on a signal band that is a band determined by the modulation rate and a device band that is a band in which a transmission path and the like allow passage of an optical signal, and controls an occurrence probability of a symbol of an optical signal based on the amplitude distribution information; and an optical transmitter that transmits an optical signal of a symbol of which the occurrence probability is controlled; and an optical reception apparatus has: an optical receiver that receives an optical signal of a symbol; a second storage unit that stores the amplitude distribution information in association with the modulation rate; and a decoding unit that detects the selected modulation rate, and decodes a symbol of a received optical signal based on the amplitude distribution information associated with the detected modulation rate.

公开(公告)号：US20200162167A1

公开(公告)日：2020-05-21

申请号：US16635130

申请日：2018-08-06

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Fukutaro HAMAOKA ,  Masanori NAKAMURA

IPC: H04B10/556 ,  H04B10/61 ,  H04B10/532

Abstract: An optical transmitter includes a first narrowband signal processing unit, a wideband signal generation unit, and an optical modulator. The first narrowband signal generation unit is configured to input a first signal and a second signal and output first, second, third and fourth narrowband signals. The wideband signal generation unit is configured to multiply the first and second narrowband signals by sinusoidal signals having a phase difference of (π/2), respectively, to shift bands of the first and second narrowband signals, and combine the shifted first and second narrowband signal to generate a first wideband signal. The wideband signal generation unit is configured to multiply the third and fourth narrowband signal by sinusoidal signals having a phase difference of (π/2), respectively, to shift bands of the third and fourth narrowband signals, and combine the shifted third and fourth narrowband signals to generate a second wideband signal.

公开(公告)号：US20160241352A1

公开(公告)日：2016-08-18

申请号：US15027610

申请日：2014-09-11

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Toshiya MATSUDA ,  Fukutaro HAMAOKA ,  Akira NAKA ,  Kohei SAITO

IPC: H04J14/02 ,  H04B10/61

CPC classification number: H04J14/02 ,  H04B10/532 ,  H04B10/5561 ,  H04B10/6151 ,  H04B10/6161 ,  H04B10/6164 ,  H04B10/6165 ,  H04J14/06

Abstract: A receiver is configured to have two coherent receivers using two pieces of local oscillator of optical frequencies f11 and f12 close to optical frequency f1 of signal light, the two pieces of local oscillator being controlled to have a predetermined optical frequency spacing ΔF, and a digital signal processor demodulating transmission data signal sequences based on outputs from the coherent receivers. When the frequency difference Δf1 of one of the two pieces of local oscillator from a virtual reference frequency f1′ close to the optical frequency f1 of the signal light is set, the digital signal processor obtains the frequency difference Δf2 of the other of the two pieces of local oscillator by calculating Δf1-ΔF, inputs electric signals output from the two coherent receivers, and compensates the phase rotation caused in the electric signals by frequency differences Δf1 and Δf2.

Abstract translation: 接收机被配置为具有两个相干接收机，它们使用接近信号光的光频率f1的两个光频本地振荡器f11和f12，两个本地振荡器被控制成具有预定的光频间隔ΔF，数字 信号处理器基于来自相干接收机的输出来解调传输数据信号序列。 当两个本地振荡器之一的频率差Δf1被设置为接近于信号光的光频率f1的虚拟参考频率f1'时，数字信号处理器获得两个的另一个的频率差Δf2 通过计算Δf1-ΔF，输入从两个相干接收机输出的电信号，并且通过频率差Δf1和Δf2补偿在电信号中引起的相位旋转。