H04L25/0314

Digital representations of analog signals and control words using different multi-level modulation formats
09755779 · 2017-09-05 · ·

A method implemented by a transmitter, comprising encoding digital in-phase and quadrature-phase (IQ) data associated with a plurality of analog signals according to a first multi-level modulation format to produce a modulated IQ signal, encoding control information associated with the plurality of analog signals according to a second multi-level modulation format that is different from the first multi-level modulation format to produce a modulated control signal, aggregating the modulated IQ signal and the modulated control signal via time-division multiplexing (TDM) to produce an aggregated TDM signal, and transmitting the aggregated TDM signal over a communication channel.

Adaptive equalizer, optical receiver, and optical transmission system

An adaptive equalizer includes a sample buffer that temporarily stores data obtained by fractional sampling at a sampling rate that is larger than one time and smaller than two times a symbol rate; and a processor coupled to the sample buffer and configured to: specify position of a training sequence in the data based on a correlation value between a first set of (f×T) samples and a second set of (f×T) samples following the first set of samples, assuming that the sampling rate is f, and a symbol length of a code pattern included in the training sequence inserted in the data is T, and calculate an initial value of a tap coefficient set to a tap of an adaptive equalization filter based on the specified training sequence, wherein the symbol length is set to be changeable so that f×T is an integer.

Adaptive equalizer, optical receiver, and adaptive equalization method

An adaptive equalizer, includes a sample buffer; and a processor coupled to the sample buffer and configured to: perform an adaptive equalization on data which has been fractionally sampled at a sampling rate higher than once a symbol rate and lower than twice the symbol rate, determine an initial value of a tap coefficient of the adaptive equalizer by using a training sequence inserted in the data, shift, by a predetermined shift amount, a sample point of one pattern from among two consecutive patterns included in the training sequence, specify a position of the training sequence in the data by replacing an original sample value with a sample value at the shifted sample point, and update the initial value of the tap coefficient based on the specified training sequence.

ADAPTIVE EQUALIZER, OPTICAL RECEIVER, AND OPTICAL TRANSMISSION SYSTEM

An adaptive equalizer includes a sample buffer that temporarily stores data obtained by fractional sampling at a sampling rate that is larger than one time and smaller than two times a symbol rate; and a processor coupled to the sample buffer and configured to: specify position of a training sequence in the data based on a correlation value between a first set of (f×T) samples and a second set of (f×T) samples following the first set of samples, assuming that the sampling rate is f, and a symbol length of a code pattern included in the training sequence inserted in the data is T, and calculate an initial value of a tap coefficient set to a tap of an adaptive equalization filter based on the specified training sequence, wherein the symbol length is set to be changeable so that f×T is an integer.

ADAPTIVE EQUALIZER, OPTICAL RECEIVER, AND ADAPTIVE EQUALIZATION METHOD

An adaptive equalizer, includes a sample buffer; and a processor coupled to the sample buffer and configured to: perform an adaptive equalization on data which has been fractionally sampled at a sampling rate higher than once a symbol rate and lower than twice the symbol rate, determine an initial value of a tap coefficient of the adaptive equalizer by using a training sequence inserted in the data, shift, by a predetermined shift amount, a sample point of one pattern from among two consecutive patterns included in the training sequence, specify a position of the training sequence in the data by replacing an original sample value with a sample value at the shifted sample point, and update the initial value of the tap coefficient based on the specified training sequence.

APPARATUSES FOR NEXT GENERATION BLOCK-WISE SINGLE CARRIER WAVEFORMS
20200267037 · 2020-08-20 · ·

Disclosed are apparatuses for a communication device. An apparatus for a communication device includes control circuitry configured to use circular convolution for pulse shape filtering of a block of data symbols of a single carrier waveform to generate a block-wise single carrier (BWSC) symbol. The apparatus is also configured to insert one of a data-based cyclic prefix or a data-based cyclic postfix into the BWSC symbol one of before the pulse shape filtering or after the pulse shape filtering. An apparatus for a communication device includes control circuitry configured to remove one or more of a cyclic prefix or a cyclic postfix from a received BWSC symbol, and use circular convolution to demodulate the received BWSC symbol.

Hybrid half/quarter-rate DFE

A two-stage decision feedback equalizer. The decision feedback equalizer is configured to receive serial data, at an analog input, at a first data rate. The two-stage decision feedback equalizer has an analog input and four digital outputs, and includes a first stage and a second stage. The first stage is connected to the analog input, and includes a half-rate predictive decision feedback equalizer consisting of current mode logic circuits. The second stage is connected to the first stage, and consists of complementary metal oxide semiconductor circuits.

HYBRID HALF/QUARTER-RATE DFE
20190273639 · 2019-09-05 ·

A two-stage decision feedback equalizer. The decision feedback equalizer is configured to receive serial data, at an analog input, at a first data rate. The two-stage decision feedback equalizer has an analog input and four digital outputs, and includes a first stage and a second stage. The first stage is connected to the analog input, and includes a half-rate predictive decision feedback equalizer consisting of current mode logic circuits. The second stage is connected to the first stage, and consists of complementary metal oxide semiconductor circuits.

Digital Representations of Analog Signals and Control Words Using Different Multi-Level Modulation Formats
20170331581 · 2017-11-16 ·

A method implemented by a transmitter, comprising encoding digital in-phase and quadrature-phase (IQ) data associated with a plurality of analog signals according to a first multi-level modulation format to produce a modulated IQ signal, encoding control information associated with the plurality of analog signals according to a second multi-level modulation format that is different from the first multi-level modulation format to produce a modulated control signal, aggregating the modulated IQ signal and the modulated control signal via time-division multiplexing (TDM) to produce an aggregated TDM signal, and transmitting the aggregated TDM signal over a communication channel.

SYSTEM AND METHOD FOR ITERATIVE COMPENSATION FOR LINEAR AND NONLINEAR INTERFERENCE IN SYSTEM EMPLOYING FTN SYMBOL TRANSMISSION RATES
20170324590 · 2017-11-09 ·

An approach for increasing transmission throughput of a non-linear wireless channel, and efficient decoding of the transmitted signal via a simplified receiver, is provided. A signal reflects a source signal, and includes linear inter-symbol interference based on a faster-than-Nyquist signaling rate and a tight frequency roll-off, and non-linear interference based on high-power amplification for transmission over the wireless channel. The signal is received over a non-linear wireless channel, and is processed via a plurality of decoding iterations. A set of soft information of a current decoding iteration is generated based on a current estimate of the source signal and a final set of soft information from a previous decoding iteration. The current estimate of the source signal is based on an estimate of the linear ISI and the non-linear interference, which is based on the final set of soft information from the previous decoding iteration.