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公开(公告)号：US12057863B2
公开(公告)日：2024-08-06
申请号：US17802071
申请日：2020-02-25
CPC分类号： H03M7/60 , H03M13/05 , H03M13/63 , H04B10/516 , H04L1/0042 , H04L1/0045 , H04L1/0057 , H04L27/34 , H03M7/14
摘要： An aspect of the present invention is a communication system including: an encoding unit configured to transform an input symbol sequence into an output symbol sequence, the input symbol sequence being a sequence of first symbols, the output symbol sequence being a sequence of second symbols; and a decoding unit configured to transform the output symbol sequence into the input symbol sequence in accordance with a decoding-side transformation mapping for transforming the output symbol sequence into the input symbol sequence that is a transformation source for the output symbol sequence, wherein the encoding unit transforms the input symbol sequence into the output symbol sequence in accordance with encoding-side transformation destination candidate information, the input symbol sequence, and a transformation probability, the encoding-side transformation destination candidate information being information indicating candidates of a transformation destination for the input symbol sequence, the transformation probability being a probability of transformation into the transformation destination indicated by the encoding-side transformation destination candidate information, and a probability of appearance of the second symbol conforms to a predefined prescribed probability distribution.
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公开(公告)号：US11799547B2
公开(公告)日：2023-10-24
申请号：US17635275
申请日：2019-09-17
IPC分类号： H04B10/079 , H04B10/2569 , H04B10/61
CPC分类号： H04B10/07951 , H04B10/2569 , H04B10/6162
摘要： A signal processing apparatus includes: a coefficient update unit configured to approximate a characteristic of a transmission line of an optical signal by a first tap coefficient vector of which an L0 norm is a predetermined value or less; a zeroing unit configured to generate a second tap coefficient vector by replacing, with 0, a tap coefficient of which an absolute value is less than a threshold among tap coefficients of the first tap coefficient vector; and an adaptive filter configured to perform, based on the second tap coefficient vector, adaptive equalization processing on a digital signal corresponding to an optical signal received via the transmission line.
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公开(公告)号：US11742950B2
公开(公告)日：2023-08-29
申请号：US17777569
申请日：2019-11-28
IPC分类号： H04B10/61 , H04B10/2513 , H04B10/079
CPC分类号： H04B10/2513 , H04B10/07951 , H04B10/6161
摘要： A computation unit uses an assumed chromatic dispersion amount to compensate for dispersion of a coherently received optical signal and performs arithmetic of a signal power of the optical signal that is dispersion compensated. The computation unit performs computation of an evaluation function when a signal power and a delayed signal power obtained by applying a predetermined delay to the signal power satisfy a threshold condition. The evaluation function is a function for evaluating whether the assumed chromatic dispersion amount is a chromatic dispersion amount of the optical signal using the difference between the signal power and the delayed signal power. The chromatic dispersion amount calculation unit calculates a chromatic dispersion amount of the optical signal based on the computation result of the evaluation function by the computation unit when each of a plurality of different assumed chromatic dispersion amounts is used.
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公开(公告)号：US11283528B2
公开(公告)日：2022-03-22
申请号：US17272790
申请日：2019-08-27
发明人： Akira Masuda , Seiji Okamoto , Shuto Yamamoto , Fukutaro Hamaoka , Masanori Nakamura , Asuka Matsushita , Yoshiaki Kisaka
IPC分类号： H04B10/61 , H04B10/079 , H04J14/06
摘要： 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.
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公开(公告)号：US11283527B2
公开(公告)日：2022-03-22
申请号：US17311928
申请日：2019-12-04
发明人： Masanori Nakamura , Fukutaro Hamaoka , Hiroshi Yamazaki , Munehiko Nagatani , Takayuki Kobayashi , Yutaka Miyamoto
摘要： 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.
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公开(公告)号：US11799557B2
公开(公告)日：2023-10-24
申请号：US17637691
申请日：2019-08-26
CPC分类号： H04B10/541 , H04L27/2605 , H04L27/2613
摘要： A communication device includes an amplitude conversion unit configured to generate a symbol sequence according to a bit sequence, a distribution matching unit configured to add redundant bits to the symbol sequence through probabilistic amplitude shaping (PAS) coding, an insertion unit configured to insert a pilot symbol into the symbol sequence to which the redundant bits have been added and transmit the symbol sequence into which the pilot symbol has been inserted to a transmission path, and a control unit configured to acquire information on the transmission path and change, according to the information on the transmission path, allocation of the redundancy of the PAS coding and the redundancy of the pilot symbol in a range of redundancy that is able to be allocated depending on a predetermined throughput.
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公开(公告)号：US11632185B2
公开(公告)日：2023-04-18
申请号：US17433149
申请日：2020-01-31
IPC分类号： H04L27/01 , H04J14/06 , H04B10/2507 , H04B10/61 , H04L27/38
摘要： A receiver convolutes each of a real component and an imaginary component of each polarization of a polarization-multiplexed reception signal with an impulse response for compensating for frequency characteristics of the receiver and a complex impulse response for wavelength dispersion compensation, and generates, as input signals, the convoluted real component and imaginary component of each polarization and phase conjugations thereof, for each polarization. The receiver generates, for each polarization, a first addition signal obtained by multiplying each of the real component and the imaginary component of each polarization by a complex impulse response, thereafter adding together the multiplied real component and imaginary component, and applying a phase rotation for frequency offset compensation to the added components, and a second addition signal obtained by multiplying each of the phase conjugation of the real component of and the phase conjugation of the imaginary component of each polarization by a complex impulse response, thereafter adding together the multiplied phase conjugations, and applying a phase rotation opposite to the phase rotation for frequency offset compensation to the added phase conjugations, and adds or subtracts a transmission data bias correction signal to or from a signal obtained by adding together the generated first addition signal and second addition signal.
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公开(公告)号：US11381317B2
公开(公告)日：2022-07-05
申请号：US17420845
申请日：2020-01-06
IPC分类号： H04B10/2513 , H04B10/61
摘要： An optical receiving device that divides receive signals obtained by receiving an optical signal using a coherent detection scheme into a plurality of frequency bands, matches timing of the receive signals along a time axis between the frequency bands resulting from the division, performs a combining process of combining the receive signals contained in the plurality of frequency bands, and compensates the receive signals for waveform distortion either before or after the combining process, includes: a first wavelength dispersion compensation unit adapted to compensate the receive signals for waveform distortion in each of the frequency bands resulting from the division; a first nonlinear compensation unit adapted to compensate the receive signals belonging to each of the frequency bands and timed with each other in a time domain for a nonlinear optical effect; and a second wavelength dispersion compensation unit adapted to compensate the receive signals belonging to each of the frequency bands and compensated for the nonlinear optical effect for wavelength dispersion in each of the frequency bands.
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公开(公告)号：US11228366B2
公开(公告)日：2022-01-18
申请号：US17269023
申请日：2020-02-03
IPC分类号： H04B10/071 , H04B10/50 , H04B10/588 , H04B10/61
摘要： A process of estimating a transfer function or an inverse transfer function of the optical transmitter from first data obtained by the optical receiver when a first known signal is transmitted from the transmitter to the receiver, and a temporary transfer function or a temporary inverse transfer function of the optical receiver, is performed for multiple frequency offsets between the optical transmitter and the optical receiver. At this time, the transfer function or the inverse transfer function of the optical transmitter is estimated by comparing the first data obtained by compensating at least one or none of a temporary transfer function of the optical receiver and transmission path characteristics detected in the receiver, with a first known signal before transmission to which what is not compensated for the first data between the temporary transfer function of the optical receiver and the transmission path characteristic is added.
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公开(公告)号：US10171173B2
公开(公告)日：2019-01-01
申请号：US15122582
申请日：2015-03-17
发明人： Seiji Okamoto , Koichi Ishihara , Etsushi Yamazaki , Mitsuteru Yoshida , Tomoyoshi Kataoka , Kazushige Yonenaga , Yoshiaki Kisaka , Masanori Nakamura , Masahito Tomizawa
IPC分类号： H04B10/50 , H04B10/516 , H04B10/2513 , H04L27/34 , H04B10/508 , H04B10/077 , H04B10/2557 , H04L27/36
摘要： An optical signal transmission apparatus includes a modulation unit which modulates a transmission signal, a training signal sequence generation unit which generates a plurality of signal sequences having power concentrated in a plurality of different frequency bands, at least one of an amplitude and a phase of the plurality of signal sequences being modulated, as a training signal sequence, a signal multiplexing unit which appends the training signal sequence to the transmission signal, and an electro-optical conversion unit which converts a signal sequence obtained by appending the training signal sequence to the transmission signal into an optical signal and transmits the optical signal.
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