Abstract: Methods, systems, and devices are described for modulating data for optical transmissions and demodulating data from optical transmissions. During modulation, bits are mapped to symbols using an 8-ary modulation scheme. The modulation scheme may be based on 8 Phase Shift Keying (8-PSK), Dual Polarization 8-PSK, or 7-1 PSK for which one of the symbols is located at or near the origin of the constellation. Streams with the symbol-mapped bits are modulated onto a waveform in the digital domain that is converted into a waveform in the analog domain before is output for conversion to an optical signal. The streams may be filtered at baseband with at least one discrete pulse-shaping filter. During demodulation, pulse-shaped data received from an optical signal and comprising symbol-mapped bits based on the 8-ary modulation scheme is sampled. The sampled data is filtered with at least one discrete pulse-shaping filter, and then equalized and demodulated.

Abstract: Methods, systems, and devices are described for modulating data for optical transmissions and demodulating data from optical transmissions. During modulation, bits are mapped to symbols using an 8-ary modulation scheme. The modulation scheme may be based on 8 Phase Shift Keying (8-PSK), Dual Polarization 8-PSK, or 7-1 PSK for which one of the symbols is located at or near the origin of the constellation. Streams with the symbol-mapped bits are modulated onto a waveform in the digital domain that is converted into a waveform in the analog domain before is output for conversion to an optical signal. The streams may be filtered at baseband with at least one discrete pulse-shaping filter. During demodulation, pulse-shaped data received from an optical signal and comprising symbol-mapped bits based on the 8-ary modulation scheme is sampled. The sampled data is filtered with at least one discrete pulse-shaping filter, and then equalized and demodulated.

Abstract: Methods, systems, and devices are described for modulating and demodulating data on optical signals. During modulation, at least one stream of symbol mapped bits is filtered with at least one pulse shaping filter to reduce a bandwidth of the stream of bits and to pre-compensate for at least one identified non-ideal transmission condition. The filtered bits are modulated onto a waveform in the digital domain, and the modulated filtered bits are transmitted to digital-to-analog converter. The output of the digital-to-analog converter is converted to an optical signal. During demodulation, a received optical signal is sampled at a first sampling rate at an ADC, downsampled to a lower sampling rate for filtering, filtered with at least one discrete pulse-shaping filter, upsampled for equalization and demodulation, and then equalized and demodulated.

Abstract: Methods, systems, and devices are described for detecting and correcting a cycle slip occurrence in a coherent receiver. Unique words are used in each received frame to detect phase changes that indicate the occurrence of a cycle slip within a frame. The location of the cycle slip is identified based on measurements made within the frame. Those measurements include phase estimation measurements and reliability measurements. A phase of a portion of the frame subsequent to the identified location of the cycle slip is adjusted to correct for the cycle slip. By combining phase estimates of symbols from both vertical and horizontal polarizations, the location of the cycle slip may be more accurately determined because the measurement windows is less susceptible to thermal noise. The phase estimates are combined by adjusting a phase of the symbols of one polarization to match a phase of the symbols of the other polarization.

Abstract: Methods, systems, and devices are described for modulating data for optical transmissions and demodulating data from optical transmissions. During modulation, bits are mapped to symbols using an 8-ary modulation scheme. The modulation scheme may be based on 8 Phase Shift Keying (8-PSK), Dual Polarization 8-PSK, or 7-1 PSK for which one of the symbols is located at or near the origin of the constellation. Streams with the symbol-mapped bits are modulated onto a waveform in the digital domain that is converted into a waveform in the analog domain before is output for conversion to an optical signal. The streams may be filtered at baseband with at least one discrete pulse-shaping filter. During demodulation, pulse-shaped data received from an optical signal and comprising symbol-mapped bits based on the 8-ary modulation scheme is sampled. The sampled data is filtered with at least one discrete pulse-shaping filter, and then equalized and demodulated.

Abstract: Methods, systems, and devices are described for modulating and demodulating data on optical signals. During modulation, at least one stream of symbol mapped bits is filtered with at least one pulse shaping filter to reduce a bandwidth of the stream of bits and to pre-compensate for at least one identified non-ideal transmission condition. The filtered bits are modulated onto a waveform in the digital domain, and the modulated filtered bits are transmitted to digital-to-analog converter. The output of the digital-to-analog converter is converted to an optical signal. During demodulation, a received optical signal is sampled at a first sampling rate at an ADC, downsampled to a lower sampling rate for filtering, filtered with at least one discrete pulse-shaping filter, upsampled for equalization and demodulation, and then equalized and demodulated.

Abstract: Methods, systems, and devices are described for a digital demodulator device for processing received optical signals. The device may include a quadrature error filter that receives a digitized version of an optical signal, and removes quadrature errors to generate a filtered series of data samples. The device may also include a frequency offset removal module for performing frequency rotation on the filtered series of data samples. The device may include a chromatic dispersion compensation module which removes chromatic dispersion from horizontal and vertical polarization channels. The device may include a polarization mode dispersion (PMD)/polarization dependent loss (PDL) compensation module which compensates for interference caused by PMD and PDL. The device may also include a phase recovery module configured to track and correct phase.

Abstract: Methods, systems, and devices are described for a digital demodulator device for processing received optical signals. The device may include a quadrature error filter that receives a digitized version of an optical signal, and removes quadrature errors to generate a filtered series of data samples. The device may also include a frequency offset removal module for performing frequency rotation on the filtered series of data samples. The device may include a chromatic dispersion compensation module which removes chromatic dispersion from horizontal and vertical polarization channels. The device may include a polarization mode dispersion (PMD)/polarization dependent loss (PDL) compensation module which compensates for interference caused by PMD and PDL. The device may also include a phase recovery module configured to track and correct phase.

Abstract: Methods, systems, and devices are described for modulating and demodulating data on optical signals. During modulation, at least one stream of symbol mapped bits is filtered with at least one pulse shaping filter to reduce a bandwidth of the stream of bits and to pre-compensate for at least one identified non-ideal transmission condition. The filtered bits are modulated onto a waveform in the digital domain, and the modulated filtered bits are transmitted to digital-to-analog converter. The output of the digital-to-analog converter is converted to an optical signal. During demodulation, a received optical signal is sampled at a first sampling rate at an ADC, downsampled to a lower sampling rate for filtering, filtered with at least one discrete pulse-shaping filter, upsampled for equalization and demodulation, and then equalized and demodulated.

Abstract: Methods, systems, and devices are described for a digital demodulator device for processing received optical signals. The device may include a quadrature error filter that receives a digitized version of an optical signal, and removes quadrature errors to generate a filtered series of data samples. The device may also include a frequency offset removal module for performing frequency rotation on the filtered series of data samples. The device may include a chromatic dispersion compensation module which removes chromatic dispersion from horizontal and vertical polarization channels. The device may include a polarization mode dispersion (PMD)/polarization dependent loss (PDL) compensation module which compensates for interference caused by PMD and PDL. The device may also include a phase recovery module configured to track and correct phase.

Abstract: Methods, systems, and devices are described for a low complexity interpolator for use in optical transmission systems. An input receives a digitized version of an optical signal, and provides samples of the received signal to a filter module. The filter module filters the input samples according to a set of filter coefficients provided by a memory. The set of filter coefficients are provided based on the output of a numerically controlled oscillator that provides an output corresponding to an accumulation of partial periods of the first sample rate. Filtered data samples are output to a sample block assembler that receives the data samples, removes filtered data samples where it is indicated that the sample is not valid, and outputs valid filtered data samples at the second sample rate and at a fixed number of samples power output period.

Abstract: Methods, systems, and devices are described for compensating for a coarse frequency offset between a received optical signal and a local oscillator at a demodulator. Multiple samples are received of an output of a discrete Fourier transform performed on the received optical signal. A magnitude of each sample is determined, and the determined magnitudes may be filtered by a digital domain filter. A difference is computed between the determined magnitudes for a first set of the samples and the determined magnitudes for a second set of the samples, and a local oscillator correction factor is generated based on at least the computed difference.

Abstract: Header information is used to facilitate coarse frequency and frame recovery. The coarse frequency and frame recovery is thereafter utilized to perform adaptive phase and frequency synchronization on a frame-by-frame basis. In one aspect, a frame identifier in a physical layer header of the digitized signal is utilized to estimate a first phase associated with the frame identifier. The remaining portion of the physical layer header is utilized to estimate a second phase associated with the remaining portion. The first phase estimate and the second phase estimate are combined to generate a first combined phase estimate.

Abstract: Methods, systems, and devices are described for a digital demodulator device for processing received optical signals. The device may include a quadrature error filter that receives a digitized version of an optical signal, and removes quadrature errors to generate a filtered series of data samples. The device may also include a frequency offset removal module for performing frequency rotation on the filtered series of data samples. The device may include a chromatic dispersion compensation module which removes chromatic dispersion from horizontal and vertical polarization channels. The device may include a polarization mode dispersion (PMD)/polarization dependent loss (PDL) compensation module which compensates for interference caused by PMD and PDL. The device may also include a phase recovery module configured to track and correct phase.

Abstract: Header information is used to facilitate coarse frequency and frame recovery. The coarse frequency and frame recovery is thereafter utilized to perform adaptive phase and frequency synchronization on a frame-by-frame basis.

Abstract: Header information is used to facilitate coarse frequency and frame recovery. The coarse frequency and frame recovery is thereafter utilized to perform adaptive phase and frequency synchronization on a frame-by-frame basis. A digitized signal representative of a wireless signal may be received. A frame identifier in a physical layer header in the signal may be identified by correlating the digitized signal to one or more known frame identifiers. The identified frame identifier may be used to estimate a phase or frequency error.

Abstract: Header information is used to facilitate coarse frequency and frame recovery. The coarse frequency and frame recovery is thereafter utilized to perform adaptive phase and frequency synchronization on a frame-by-frame basis.

Abstract: Header information is used to facilitate coarse frequency and frame recovery. The coarse frequency and frame recovery is thereafter utilized to perform adaptive phase and frequency synchronization on a frame-by-frame basis. A digitized signal representative of a wireless signal may be received. A frame identifier in a physical layer header in the signal may be identified by correlating the digitized signal to one or more known frame identifiers. The identified frame identifier may be used to estimate a phase or frequency error.

Abstract: An architecture for the dynamic assignment of links in a multi-user communication system. A plurality of information channels are provided in a forward communication link of the communication system for carrying channel information of the plurality of information channels from a transmitter to a plurality of corresponding receiving devices. The channel information in corresponding select ones of the plurality of information channels is varied dynamically in response to link conditions of the associated receiving devices to more efficiently utilize the channel bandwidth.

Abstract: Architecture for processing a record of burst information in a transmission link. A waveform sampler samples a received waveform containing a record of symbols imposed on a carrier signal. Symbol phase of the record symbols is determined utilizing one or more metrics. Any residual carrier error is corrected, and the carrier signal is removed. The phase and time-of-arrival of the burst information associated with a maximum positive correlation value are then determined.