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: Polarization mode dispersion (PMD) in a dual-pole optical communications network is compensated for using an adaptive PMD equalizer. The PMD equalizer may include a number of substantially identical filter modules that provide partial outputs which may be combined to form a PMD compensated output. A constant modulus algorithm (CMA)-based equalizer may track PMD across both poles and generates an error signal. The CMA-based equalizer includes a filter bank, and uses an update algorithm and tap/output adjustments based on a difference between combined tap energies and an index, and feedback from a forward error correction code frame synchronizer.

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: A soft-decision forward error correction scheme for received optical signals is described. Differential decoding may be performed, for example, in each polarization after coherent QPSK detection. Hard decisions may be made based on judging the most likely transition between each pair of received input symbols. Soft-input generation is also described, representing the reliability of the hard decisions. The soft-input information may be generated through simplified algorithms that utilize the most likely transitions to determine a reliability assignment.

Abstract: Methods, systems, and devices are described for tap adjustment and reseeding in a digital filter. Filter and signal characteristics are measured and tap adjustments and reseeding of tap values may be performed based on the filter and signal characteristics. Filter characteristics that may be measured include a filter center of mass which may provide an indication that filter taps for a filter may be drifting toward a filter edge and thus reducing the dynamic range of the filter. Signal characteristics may include a timing offset between received input signals, and characteristics related to which of a particular input signal is present at a filter output. Filter taps, according to various embodiments, may be adjusted, and/or re-initialized responsive to one or more of the signal or filter characteristics.

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: Various exemplary embodiments relate to a method performed by a policy and charging rules node for managing usage of a subscriber. The method may include: defining a primary metering policy having a first applicability condition and a first quota; defining a secondary metering policy having attributes including a second applicability condition and at least one inherited attribute that references an attribute of the primary metering policy; determining that the second metering policy is applicable when the first applicability condition and the second applicability condition are true; selecting the secondary metering policy as an active metering policy; and managing subscriber usage according to the attributes of the secondary metering policy.

Abstract: Compensation for in-phase (I) and quadrature (Q) timing skew and offset in an optical signal may be achieved based on the correlation between derivatives of I and Q samples in the optical signal. The magnitude of the correlation between derivatives is measured to determine the presence of skew. Correlation between derivatives may be coupled with frequency offset information and/or with trials having additional positive and negative skew to determine presence of skew. Correlations are determined according to pre-defined time periods to provide for continued tracking and compensation for timing skew that may result from, for example, thermal drift.

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 formatting of data streams to be transmitted over fiber optic channels, and for processing received optical signals. A data transmission device may include a digital coding and modulation module that encodes a digital data stream, inserts unique words into the digital data stream, and modulates the encoded data stream and unique words onto optical channels for transmission over an optical fiber. A demodulation and decoding device may include a unique word identification module that identifies the unique words inserted in each optical channel stream, determines one or more characteristics of the plurality of optical channels based on the unique words, and provides the one or more characteristics to one or more other modules in the demodulator and decoding device.

Abstract: Various exemplary embodiments relate to a method and related network node including one or more of the following: receiving, at the PCRN, a request for establishment of a new service data flow (SDF) for a subscriber; generating a policy and charging control (PCC) rule based on the request; identifying a first metering object of a plurality of metering objects as currently applicable to the subscriber, wherein the first metering object includes a first monitoring key; and transmitting the PCC rule and the first monitoring key to the PCEN for installation. Various embodiments additionally include, after transmitting the PCC rule and the first monitoring key. identifying a second metering object of the plurality of metering objects as currently applicable to the subscriber, wherein the second metering object includes a second monitoring key; and transmitting the second monitoring key to the PCEN for installation in association with the PCC rule.

Abstract: Various exemplary embodiments relate to a method and related network node including one or more of the following: determining that a service should be configured for a subscriber; identifying a metering object that is currently applicable to the subscriber, wherein the metering object includes a metering limit and a plurality of actions; selecting a first action of the plurality of actions, wherein the first action includes a first parameter; configuring the service on the PCEN according to the first parameter, wherein configuring the service comprises instructing the PCEN to report usage of the service; and applying the metering limit to usage reported by the PCEN.

Abstract: Soft bit metric generation computational complexity can be reduced by identifying and utilizing only the dominant terms in a reliability calculation such as a logarithmic likelihood ratio (LLR). The dominant terms are those terms for which the signs of the x and y components match those of channel outputs of the channel outputs. One technique for identifying the dominant terms is by determining the most likely transitions from two consecutive channel output samples Values for the dominant terms can be estimated by either the joint reliability of two consecutive samples of the in-phase component (x1,x2) or by the joint reliability of two consecutive samples of the quadrature components (y1,y2).

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: Various exemplary embodiments relate to a method performed by a policy and charging rules node (PCRN), the method including: receiving a metering limit associated with a user; defining a session key associated with the metering limit; defining a flow key associated with the metering limit; dynamically selecting the session key; commanding a policy and charging enforcement node to apply the dynamically selected session key to a session of the user; dynamically selecting the flow key; and commanding a policy and charging enforcement node to uninstall the session key and to apply the dynamically selected flow key to a flow of the user.

Abstract: Various exemplary embodiments relate to a method for determining the usage of a subscriber to mobile and fixed line services including: receiving subscriber usage information from a fixed line network; receiving subscriber usage information from a mobile network; computing a usage metric based upon the received subscriber usage information from the fixed line network and the mobile network and rating factor information; comparing the usage metric to a predetermined usage threshold; determining a usage policy action; and transmitting a usage policy action message.

Abstract: A method for hierarchical communication of a set of source data includes: receiving source data representing content to be communicated to a data terminal; pre-coding at least some of the source data using pre-coding schemes to generate sets of representation data; associating the sets of representation data with coding and modulation schemes; generating transmissions by applying the coding and modulation schemes to the sets of representation data; transmitting a first transmission to the data terminal on a first communication link; and transmitting a second transmission to the data terminal on a second communication link, wherein the second communication link differs from the first communication link.

Abstract: Systems, devices, and methods are disclosed for a novel edge memory architecture. An architecture is described wherein the extrinsic information typically stored inside the edge memory is reformatted. Instead of storing the extrinsic information for every edge, the novel edge memory stores a set of possible extrinsic information values for a check node in a “value memory.” The edge memory also stores an index for each edge in a second, “index memory,” identifying which value stored in the value memory applies to each respective edge.

Abstract: Methods, systems, and devices are described for formatting of data streams to be transmitted over fiber optic channels, and for processing received optical signals. A data transmission device may include a digital coding and modulation module that encodes a digital data stream, inserts unique words into the digital data stream, and modulates the encoded data stream and unique words onto optical channels for transmission over an optical fiber. A demodulation and decoding device may include a unique word identification module that identifies the unique words inserted in each optical channel stream, determines one or more characteristics of the plurality of optical channels based on the unique words, and provides the one or more characteristics to one or more other modules in the demodulator and decoding device.

Abstract: Embodiments of the invention provide a Policy and Charging Rules Function (PCRF) node and a method for authorizing a Quality of Service (QoS) for a wireless subscriber based on subscriber usage and time-of-day for a 3GPP-compliant packet data network