Mitsubishi Electric Corporation

Mitsubishi Denki Kabushiki Kaisha

Kdd Submarine Cable Systems, Inc.

Kdd Corporation

Kazuo Kubo

Hideo Yoshida

Takashi Mizuochi

Yoshikuni Miyata

Yoshiaki Konishi

Hiroshi Ichibangase

Takashi Sugihara

Kenya Sugihara

Kenji Ishii

Yuji Akiyama

Seiji Kozaki

Kiyoshi Onohara

Hachiro Fujita

Eiichi Shibano

Tadami Yasuda

Tatsuya Kobayashi

Junichi Abe

Tsuyoshi Yoshida

Hirofumi Totsuka

Wataru Matsumoto

Hidenori Taga

Katsuhiro Shimizu

Keisuke Matsuda

Kuniaki Motoshima

Hiroki Goto

Takahiko Nakamura

Aritomo Uemura

Masashi Binkai

Yuta Takemoto

Soichiro Kametani

Kazushige Sawada

Kazuumi Koguchi

Koichi Takizawa

Kazuhide Ouchi

Eiichi Horiuchi

Yasuyuki Endoh

Eiji Nagatake

Sota Yoshida

A transmitter according to the disclosure includes: an encoding unit that generates a code word by performing coding with a low-density parity-check code using a check matrix, the encoding unit being capable of switching the check matrix for use in generating the code word, between a first check matrix with a first code rate and a second check matrix with a second code rate smaller than the first code rate, the first check matrix containing a plurality of cyclic permutation matrices, the encoding unit generating the second check matrix by masking the cyclic permutation matrix at a predetermined position in the first check matrix and adding a row with a column weight equal to or less than a threshold; and a transmission unit that transmits the code word.

Transmitter, receiver, communication system, method for changing code rate, control circuit and non-transitory storage medium

Provided is an optical transmission/reception device including: an error correction encoding unit configured to encode a sequence to be transmitted with one type of LDPC code; and an error correction decoding unit configured to decode a received sequence encoded with the LDPC code. The error correction decoding unit performs decoding processing for the received sequence based on a check matrix of an LDPC convolutional code. The decoding processing is windowed decoding processing, which is performed by using a window extending over one or more check submatrices. A window size of the window and a decoding iteration count are configured to be variable, and the window size and the decoding iteration count are input from a control circuit connected to the error correction decoding unit.

Error correction device and optical transmission/reception device

Provided is an optical transmission/reception device including an error correction decoding unit () for decoding a received sequence encoded with an LDPC code, in which the error correction decoding unit () is configured to perform decoding processing using a parity check matrix () of a spatially-coupled LDPC code, which includes a plurality of parity check sub-matrices () combined with each other, in which the decoding processing is windowed decoding processing that uses a window () over one or more parity check sub-matrices (), and in which a window size of the window () and a decoding iteration count due to throughput and requested correction performance are variable and input from a control circuit () connected to the error correction decoding device ().

Error correction decoding device and optical transmission/reception device

Provided is an error correction device including an encoding circuit configured to encode a plurality of error correction code sequences, in which the encoding circuit includes a plurality of encoding circuits connected in parallel, and is configured to execute encoding processing for the plurality of error correction code sequences through use of all the plurality of encoding circuits by adjusting an output bus width and a frequency of an operation clock with respect to a difference in transmission rate for any payloads input in one or more systems.

Error correction device and error correction method

An optical transmission method wavelength-multiplexing and transmitting multiple channels including data. The data are composed of data areas independent between the channels and data areas non-independent between the channels. Data patterns of the data areas non-independent between the channels are variable. The data patterns of the data areas non-independent between the channels are set so that in time periods of the non-independent data areas on an optical transmission section, a time period during which polarization states of the multiple channels are correlated in the optical transmission section has a length such that an error rate is less than or equal to a threshold value, the error rate being determined from a temporal distribution of bit errors obtained from a result of error decision after demodulation in an optical receiver.

Optical transmission method and optical transmission system

A transmission device of a signal transmission system multiplexing and transmitting a plurality of 8B10B-coded information sequences, which includes: conversion units the number of which is identical to the number of the information sequences, to perform 8B10B-decoding of each of the information sequences, receive one of the information sequences after the decoding, scramble the received information sequence, and add a synchronous pattern indicating a head of a frame to the scrambled information sequence; and a multiplexing unit to multiplex the information sequence outputted from each of the conversion units.

Transmission device, communication device and signal transmission system

A delay measuring device of a communication system that includes the delay measuring device sequentially transmitting and receiving frames having a known frame length, and a measurement object device serving as an object for measuring a round trip time by the delay measuring device, includes: an RTT measuring unit to measure a round trip time with respect to the measurement object device a number of times using information for delay measurement in the frame; an RTT change detection unit to detect a change of a value of the round trip time based on the values of the round trip time thus measured; and an RTT determination unit to determine a value of the round trip time to be adopted, from among the values of the round trip time, based on the change of a value of the round trip time.

Delay measuring device, measurement object device and communication system

A likelihood generation apparatus for acquiring a likelihood of a 16QAM signal includes a first likelihood generation unit configured to generate a likelihood of each of two bits of a 16QAM signal point of the 16QAM signal from a relationship of each of an I-axis component and a Q-axis component with a likelihood when the 16QAM signal point is mapped on a constellation diagram, and a second likelihood generation unit configured to generate a likelihood of each of remaining two bits other than the two bits of the 16QAM signal point of the 16QAM signal based on a position of the 16QAM signal point in a lookup table, which is configured to input the I-axis component and the Q-axis component of the 16QAM signal point as arguments, and includes regions acquired by dividing the constellation diagram based on a possible value of each of the bits.

Likelihood generation apparatus and method therefor

An optical transmission apparatus that accommodates client signals in a line signal, includes: an OPUn mapper unit that receives and maps the client signals; and a mapping control unit that determines the number of pieces of client data to be mapped to a payload portion and determines the timing to insert client data and information on the number of pieces of client data into the payload portion to control mapping performed in the OPUn mapper unit.

Optical transmission apparatus and optical reception apparatus

Provided is an optical communication cross-connection device for exchanging an OTN signal through optical communications, including: a plurality of OTN signal processing units (OTNsp units) for asynchronously conducting OTN signal processing; and a space switch connected between the plurality of OTNsp units, for conducting bidirectional signal exchange for the OTN signal, in which a first and a second OTNsp units that conduct signal transmission among the plurality of OTNsp units subject the OTN signal to skew processing on one side and deskew processing corresponding to the skew processing on another side between the first and second OTNsp units or between a communicating end-side one of the first and second OTNsp units and a communicating end-side OTNsp unit of an optical communication cross-connection device of a communication counterpart destination for the optical communication cross-connection device, and share a clock for the signal transmission therebetween.

Optical communication cross-connection devices and signal processing method thereof

An optical transmission device for transmitting and receiving a multilevel-modulated optical signal includes a plurality of transmission frame processors for generating transmission frame signals accommodating a plurality of client signals that are each subjected to error correction processing and scrambling/descrambling processing, and a digital modulator/demodulator for mapping the transmission frame signals that are input to and output from the plurality of transmission frame processors to a multilevel signal. The digital modulator/demodulator performs digital modulation/demodulation, in which the plurality of transmission frame processors each have a function of shifting a phase of a pattern between a plurality of transmission frames to be mapped to a multilevel signal and to be digitally modulated/demodulated.

Optical transmission device

A frame generation method in an optical transmission system that transmits a transmission frame including a payload area for storing therein information data and an FEC redundant area for storing therein an error correcting code with respect to the information data is provided, in which coding gain is calculated based on the quality of a communication path through which the transmission frame is transmitted, and, when it is determined that redundancy is insufficient with an error correcting code stored in the FEC redundant area based on the coding gain, a variable parity area for storing therein the error correcting code is set in the payload area and a transmission frame in which the error correcting code is stored in the FEC redundant area and the variable parity area is generated.

Frame generation method, optical transmission device, and optical transmission system

Provided is an error correction encoder that performs coding on both a transmission area and a redundancy area of the transmission frame by using a product code, and when excess or deficiency is arisen with respect to allocation of an information sequence area and/or a parity sequence area in a product code frame generated by the coding using the product code, non-uniformly allocate the information sequence area to the parity sequence area, and/or non-uniformly allocate the parity sequence area to the information sequence area, where each of the non-uniform allocations is performed in accordance with the arisen excess or deficiency.

Error correction coding device, error correction decoding device and method therefor

An input bit error ratio estimating method executed by a communication control unit includes a computing, a condition determining, a first input BER estimating, a second input BER estimating, a third input BER estimating, and an input BER estimation result outputting. In the condition determining, the communication control unit determines which of a plurality of conditions set in advance to be narrowed down to one has been established, based on a post-internal decoding residual error detection ratio. Based on the condition that is determined in the condition determining as one that has been established, the communication control unit selects one out of a plurality of processing procedures for estimating the input BER, namely, selects one of the first input BER estimating to the third input BER estimating and executes the selected processing.

Method and device for estimating input bit error ratio

An error-correction coding method that includes outer coding of performing a coding process for an outer code; and inner coding of performing a coding process for an inner code that has an error correction capability adjusted based on an error correction capability of the outer code.

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Tokyo, Japan

Kazuo Kubo