公开(公告)号：US20250055568A1

公开(公告)日：2025-02-13

申请号：US18719033

申请日：2021-12-17

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryo IGARASHI ,  Kazutaka HARA ,  Ryo KOMA ,  Takahiro SUZUKI

IPC: H04B10/293 ,  H04Q11/00

Abstract: A signal intensity flattening method includes: classifying a plurality of user devices accommodated in the same relay node so that user devices with similar optical signal intensities are in the same class; and setting a signal transmission path for converging optical signals transmitted from user devices of the same class in the same optical transmission line, and adjusting the signal intensities of the optical signals converged in the same optical transmission line collectively without separating them for each wavelength.

公开(公告)号：US20240230832A1

公开(公告)日：2024-07-11

申请号：US18562439

申请日：2021-05-20

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Naotaka SHIBATA ,  Takeshi Imai ,  Ryo IGARASHI ,  Kazutaka HARA

IPC: G01S5/16 ,  H04W4/021 ,  H04W64/00

CPC classification number: G01S5/16 ,  H04W4/021 ,  H04W64/003

Abstract: One aspect of the present invention is a decision device including: a position information acquisition unit that acquires position information indicating a position where the lighting device is installable and an irradiation target region that is irradiated with light in a case where the lighting device is installed at the position; an adjacency information acquisition unit that acquires adjacency information indicating an adjacency relationship of the irradiation target region on the basis of the position information acquired by the position information acquisition unit; and a decision unit that decides the installation position of the lighting device on the basis of the adjacency information acquired by the adjacency information acquisition unit such that non-irradiation target regions are not adjacent to each other, the non-irradiation target regions being not irradiated with light whose output mode changes due to non-installation of the lighting devices.

公开(公告)号：US20240200950A1

公开(公告)日：2024-06-20

申请号：US18287979

申请日：2021-05-20

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Kazutaka HARA ,  Ryo IGARASHI ,  Junichi KANI ,  Naotaka SHIBATA ,  Takeshi IMAI

IPC: G01C21/20 ,  H04B10/116

CPC classification number: G01C21/206 ,  H04B10/116

Abstract: An aspect of the present invention is a moving body that moves along a rail, the moving body including: a light emission unit; a movement control unit that controls the moving body so as to move on the rail at a predetermined speed; a measurement unit that measures a movement time of moving from a predetermined position on the rail; and a transmission unit that transmits a signal indicating position information corresponding to the movement time measured by the measurement unit by using the light emission unit.

公开(公告)号：US20230318713A1

公开(公告)日：2023-10-05

申请号：US18024853

申请日：2020-09-09

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryo IGARASHI ,  Masamichi FUJIWARA ,  Junichi KANI

IPC: H04B10/516 ,  H04B10/50 ,  H04B10/64

CPC classification number: H04B10/516 ,  H04B10/503 ,  H04B10/64

Abstract: An optical transmission apparatus includes an optical transmitter that generates an optical signal in an uplink direction by modulating output light of a laser that outputs light of a first frequency with a subcarrier on which transmission data is superimposed, a heterodyne detection unit that receives an optical signal in a downlink direction by heterodyne detection, a control unit that calculates a first intermediate frequency based on the frequency of the downlink signal received by the heterodyne detection and the first frequency of the laser, and controls the first frequency of the laser when there is a difference between the calculated first intermediate frequency and a reference second intermediate frequency by a threshold or more.

公开(公告)号：US20240031035A1

公开(公告)日：2024-01-25

申请号：US18026559

申请日：2020-09-23

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryo IGARASHI ,  Masamichi FUJIWARA ,  Takuya KANAI

IPC: H04B10/61

CPC classification number: H04B10/616

Abstract: A coherent optical reception device includes a coherent receiver that receives signal light in which an AMCC signal is superimposed on a main signal by phase modulation and outputs a reception signal and a digital signal processor, in which a modulation signal of the AMCC signal superimposed on the main signal is multiplied by a clock, the digital signal processor includes a symbol output, an AMCC signal code sequence demodulator, and a main signal code sequence demodulator, and the AMCC signal code sequence demodulator includes a main signal component remover that removes the main signal included in the reception signal output from the symbol output, and a clock component remover that removes a clock component included in the reception signal from which the main signal has been removed by the main signal component remover.

公开(公告)号：US20230198630A1

公开(公告)日：2023-06-22

申请号：US17924140

申请日：2020-06-08

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryo IGARASHI

IPC: H04B10/61

CPC classification number: H04B10/6164 ,  H04B10/6162

Abstract: An optical reception apparatus includes: an optical coherent reception unit that receives a frequency-modulated optical signal whose optical intensity is approximately constant and generates an I-axis component of a reception signal and a Q-axis component of the reception signal based on the optical signal; a conversion unit that generates a digital signal of the I-axis component of the reception signal and a digital signal of the Q-axis component of the reception signal; a differential detection unit that generates a differential detection signal by controlling a delay amount of the digital signal of the I-axis component and a delay amount of the digital signal of the Q-axis component so that a distance between symbols on an IQ plane is increased and by performing differential detection on the digital signal of the I-axis component whose delay amount is controlled and on the digital signal of the Q-axis component whose delay amount is controlled; and an inter-symbol-distance measuring unit that measures a distance between the symbols based on a phase change amount of the differential detection signal and feeds the distance between the symbols back to the differential detection unit.

公开(公告)号：US20230188208A1

公开(公告)日：2023-06-15

申请号：US17924149

申请日：2020-05-28

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryo IGARASHI ,  Masamichi FUJIWARA ,  Takuya KANAI

IPC: H04B10/071

CPC classification number: H04B10/071

Abstract: A light leakage confirmation method comprising: an excitation light incident step in which an excitation light output unit connected to a first end of a first optical transmission line outputs an excitation light and makes the excitation light incident on the first optical transmission line; a reflection step in which an excitation light reflection unit connected to a second end of the first optical transmission line reflects the excitation light which has been incident in the excitation light incident step; a reflected light incident step of making a reflected light which has been reflected in the reflection step incident on the first optical transmission line; a reflected light measurement step in which the excitation light output unit measures an intensity of the reflected light; and a leakage determination step of determining whether or not the excitation light is leaked on a basis of the intensity of the excitation light and the intensity of the reflected light which has been measured in the reflected light measurement step.

公开(公告)号：US20230163852A1

公开(公告)日：2023-05-25

申请号：US17908527

申请日：2020-03-04

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryo IGARASHI ,  Masamichi FUJIWARA ,  Kazutaka HARA ,  Takuya KANAI ,  Yasutaka KIMURA ,  Atsuko KAWAKITA

IPC: H04B10/2575 ,  H04B10/278 ,  H04J14/02

CPC classification number: H04B10/25756 ,  H04B10/278 ,  H04J14/0202

Abstract: An optical communication system configured with a station-side apparatus and a plurality of subscriber-side apparatuses in a bus network topology includes an optical amplification unit installed on a station side, and a drop unit configured to branch an optical signal and excitation light, wherein the optical amplification unit includes an amplifier configured to amplify a downlink signal, and an excitation light output unit configured to output the excitation light for amplifying an uplink signal to a communication path, and the drop unit changes a branching ratio in accordance with a wavelength of the optical signal so that a transmission loss of the excitation light with respect to a trunk fiber is reduced.

公开(公告)号：US20230344522A1

公开(公告)日：2023-10-26

申请号：US18026550

申请日：2020-09-23

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryo IGARASHI ,  Masamichi FUJIWARA ,  Takuya KANAI

IPC: H04B10/61

CPC classification number: H04B10/61

Abstract: A coherent optical reception device includes a coherent receiver that receives signal light in which an AMCC signal is superimposed on a main signal, converts the signal light into an analog electric signal, and outputs an in-phase component and a quadrature-phase component of a reception signal for each polarization state, and a polarization combiner that performs polarization combining on the in-phase component and the quadrature-phase component of the reception signal output from the coherent receiver for each polarization state and outputs the reception signal as an AMCC signal identification reception signal that is the reception signal used for identification of the AMCC signal and a main signal identification reception signal that is the reception signal used for identification of the main signal.

公开(公告)号：US20210399809A1

公开(公告)日：2021-12-23

申请号：US17271169

申请日：2019-08-30

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryo IGARASHI ,  Masamichi FUJIWARA ,  Takuya KANAI

IPC: H04B10/61 ,  H04B10/077 ,  H04L27/20 ,  H04L27/22

Abstract: Upon receipt of a coherent optical signal that includes a training signal generated using a code sequence constituted by multi-value phase modulation symbols, in which a deviation angle of a vector average of a one-symbol delay differential component of a signal generated on the basis of the code sequence has a prescribed angle and a modulation phase difference between adjacent symbols has a fixed, repeated pattern, a reception training signal corresponding to a training code sequence for frequency offset estimation is detected within a reception signal acquired by converting the received coherent optical signal into an electric signal, a plurality of delay differential components are calculated on the basis of the detected reception training signal and at least two delay signals of the reception training signal, each delay signal having a different number of delay symbols, and an averaged frequency offset amount is calculated using the calculated plurality of delay differential components.