Abstract: Precoding mitigates or removes interference signals (especially crosstalk) among multiple users with interconnected transmitters in vectored DSL systems and the like. Efficient implementation is provided of the R matrix in RQ factorization that characterizes multi-user downstream vector channels (such as DMT VDSL one-sided or two-sided transmission channels). A set of precoder coefficients can vary with each tone used by each user and depend upon the encoding order of users selected for each tone. In adaptive operation, the coefficients of the R and Q matrices can be updated when changes occur to the transmission environment. Variable modulo arithmetic mitigates the power-enhancement problem, and the base of modular arithmetic also can vary with each user within a single precoder for a single tone.

Abstract: Existing and future standardized VDSL2 and other systems can be integrated into and used with a vectored DSLAM or other vectored or non-vectored DSL system, without a new user disrupting service to other users in the same or a nearby binder, in some cases by using transmit power, CARMASK and/or PSDMASK DSL capabilities to reduce both downstream and upstream training-signal levels so that training of a new DSL line is non-disruptive, despite a lack of knowledge of the pre-existing binder. For vectored systems, the crosstalk from that tone can be observed, learned and then added to the vectoring system so that any subsequent excitation on that tone would be eliminated by vector processing. A second tone then can be added in the same way, etc. In non-vectored DSLs that might be operating in a binder or line set, once these non-vectored lines are observed to be present, a vectored line set controller, such as a DSL optimizer, then can anticipate the potential interference from such non-vectored lines.

Abstract: Adaptive generalized decision feedback equalization (GDFE) allows variations in one or more channels and noise of a multi-line/multi-channel communication system to be tracked. Such tracking can be used in vector upstream (one-sided) situations in communication systems such as ADSL and VDSL, among others. The GDFE may be separated into adaptive and static portions and/or components. Either a feedforward section or a feedback section (or both) can be separated to create a static component and an adaptive component. The adaptive components adjust to the instantaneous channel and noise changes (for example, using the instantaneous errors and simple LMS algorithms). When the channel and noise do not exhibit any time-variation, the adaptive filters can zero themselves.

Abstract: Methods, apparatus, computer program products and other embodiments model a system's channel and noise characteristics using one or more Hidden Markov Models (HMMs) by modeling the state dynamics for one or more lines and associated profiles and by learning from the line history. Besides channel and noise characteristics, user data activity also can be modeled using an HMM, where all channel, noise and user data activity can be modeled jointly using HMMs as long as the joint states are properly defined. In multi-line systems, multiple lines (for example, a set of lines in a DSL system binder) may be modeled jointly. After learning channel, noise, user data activity and/or other dynamics using HMM techniques and methods, system operation and/or configuration parameters can be controlled based on the estimated HMM, providing flexible solutions for virtually any channel, noise, user data activity and/or other dynamics.

Abstract: Superimposing phantom-mode signals reinforces existing differentially driven DSL downstream signals in a vectored binder of DSLs or reinforces upstream vectored signals in a binder of differentially excited twisted pairs, thus expanding the extra transmission modes of the previous GDSL multi-wire two-sided-excitation invention to the case where coordination can only occur on one-side of the binder. Each pair is treated as a common-mode antenna with respect to earth ground, with some pairs selectively excited at the transformer center tap at the transmit end with respect to a common (earth or chassis) ground reference. Corresponding receivers on other non-excited pairs sense the signals between their center taps and a ground at the opposite ends of the lines to the exciting transmitters. A dual use with hybrid circuits allows the receiving circuit to also have an upstream transmitter and an upstream-sensing receiver on the center tap of the opposite side of an adjacent wire.

Abstract: A set of complex rotations are used to implement a unitary “Q” matrix that can arise in various transmitters and/or receivers in communication line vectoring. Each complex rotation is a set of real rotations, where the minimum number of real rotations to perform the complex rotation is three, and where the minimum number of angles to characterize the real rotations is two. An order of rotations is also provided. The invention assists in the efficient implementation of any unitary “Q” matrix in a QR or other sophisticated matrix factorization.

Abstract: Transitions between states and/or profiles for a line in a communication system, such as a DSL system, are controlled by evaluating the current state of the line and one or more target states. Evaluation of the feasibility of staying in the current state or moving to one of the target states can be based on distributions of reported and estimated data distilled from operational data collected from the communication system. The target states may be prioritized and arranged in a matrix. Feasibility may take into account both the sufficiency of available data and the line's likely behavior in the current state and any potential target state. Probabilities of meeting operational and/or performance thresholds can be used in various sub-rules whose outputs can be combined in an overall rule that provides a feasibility or infeasibility decision. Old data can be weighted or completely purged to control its influence on a potential transition.

Abstract: A system and method are described for selecting a service state using a configurable abstraction layer. A comparison is made between network parameters of a Network Performance Layer and network services of a Service Layer. Once network parameters are within a threshold for providing a given service, a state change can be made in the configuration parameters to suit the provided service.

Abstract: Estimates of a communication system configuration, such as a DSL system, are based on operational data collected from a network element management system, protocol, users and/or the like. The operational data collected from the system can include performance-characterizing operational data that typically is available in an ADSL system via element-management-system protocols. Generated estimates and/or approximations can be used in evaluating system performance and directly or indirectly dictating/requiring changes or recommending improvements in operation by transmitters and/or other parts of the communication system. Data and/or other information may be collected using “internal” means or may be obtained from system elements and components via email and/or other “external” means.

Abstract: Information is sent by a DSL system component using a non-disruptive operational data parameter. One or more bits of the non-disruptive operational data parameter are used to send other information. In some instances the selected parameter will be an unused parameter, such as an unused fast operational mode or interleaved operational mode parameter used to report operational data in a DSL system. In one embodiment of the invention, a remote modem provides a unique equipment identifier that can be paired with the telephone number on which the modem is operating. Verification of and/or searching for the correct pairing of telephone number and unique equipment identifier can be performed as well.

Abstract: A DSL or other communication system includes a modem or other communication device having at least one antenna that is configured to collect interference data relating to interference noise affecting communication signals being received by the communication device. The interference may include RF interference, such as AM radio interference, crosstalk and other types of interference from various sources. The interference data collected by the antenna is used by an interference canceller to remove and/or cancel some or all of the interference affecting received signals. In some embodiments of the present invention, more than one antenna may be used, wherein each antenna can collect interference data pertaining to a single source of interference noise. Where a modem or other communication device is coupled to multiple telephone lines, only one of which is being used as the active DSL line, wires in the remaining telephone lines or loops can be used as antennas.

Abstract: Improved DSL and/or other communication system services can be provided by motivating users, service providers and operators to implement and comply with one or more operational conditions, such as parameter value limits and/or ranges, that enhance operation of the communication system. Enhanced operation can include providing a reward such as an operational benefit to one or more users and/or mitigating problems experienced by other users in the communication system, which can be one or more communication lines. A DSL line implementing and complying with one or more operational conditions is provided with a reward (such as an operational benefit like a higher maximum data rate), which is otherwise withheld if the line fails to comply with the condition(s). Each operational condition may be set and monitored by a controller, such as a DSL optimizer that collects and analyzes operational data to determine compliance.

Abstract: Operational data is utilized to determine the FEXT interference induced by one line into the other DSL line. FEXT interference can be calculated using the NEXT interference measured between the two lines at the upstream ends of the loops and the downstream channel transfer function of one of the loops. Because the NEXT and transfer function constitute a linear time-invariant system, as does the FEXT interference between the lines, the NEXT interference and line transfer function can be multiplied (if in linear format) or added (if in logarithmic format) to approximate the FEXT interference between the lines. The collection of data, calculations and other functions performed in these techniques may be performed by a system controller, such as a DSL optimizer.

Abstract: A DSL system includes a multiple loop segment where K loops are bonded to provide a multiple loop segment having up to (2K?1) communication channels on which transmissions are vectored. The segment may be a drop to a customer premises, an inter-pedestal link, or any other suitable part of a larger DSL system. Generally the bonded loops are relatively short, being 300 meters or less. Signal vectoring is used to increase the speed and data carrying capability of the channels. In some embodiments, an expanded frequency spectrum also can be used to increase the data carrying capability of one or more of the channels. An impedance matching circuit may be coupled to each end of the segment to provided efficient transmission of data across the segment. A controller may provide control signals used to operate the segment as a vectored system and, if desired, frequency bandwidth control signals. The controller may monitor and/or collect data and information from the DSL system to assist in generating control signals.

Abstract: Adaptive FEC coding is used to adjust the codeword composition of FEC codewords in a communication system. A codeword composition ratio may be adjusted in response to variance of a measured transmission error value from a target transmission error value in the system. The codeword composition ratio may be any quantity or value that represents the relation between the payload and parity bytes in the applicable FEC coding scheme. Adjustment of the codeword composition ratio may be adjusting parameters such as the N, K and/or R values in ADSL1 systems or the INP and/or maximum interleaving delay values in ADSL2 systems. A controller may be used to monitor, analyze and adjust the various values used in adaptively managing FEC coding. The present invention may be implemented in a transmission system in which a transmitter transmits data to a receiver via a transmission channel, such as a DSL system.

Abstract: Estimates of a communication system configuration, such as a DSL system, are based on operational data collected from a network element management system, protocol, users and/or the like. The operational data collected from the system can include performance-characterizing operational data that typically is available in an ADSL system via element-management-system protocols. Generated estimates and/or approximations can be used in evaluating system performance and directly or indirectly dictating/requiring changes or recommending improvements in operation by transmitters and/or other parts of the communication system. Data and/or other information may be collected using “internal” means or may be obtained from system elements and components via email and/or other “external” means.

Abstract: Controlling margins in a DSL modem pair is based on collected operational data. The operational data is analyzed and at least one of the modems in the modem pair is instructed to use a margin-related parameter value to assist the modem pair in meeting a margin target, such as a margin limit imposed by a DSL standard or the like. A controller, such as a DSM Center, a “smart” modem unit and/or a computer system can collect and analyze the operational data and generate one or more margin-related parameter values. The margin-related parameter value may be a PSD-related value, such as the MAXNOMPSD, MAXNOMATP or PSDMASK parameter used by various ADSL systems, and may be a shaped spectral mask and/or caps or limits on bit loading for use in transmissions between the modems. In some cases, preference bands can be imposed to direct modems to favor and/or avoid certain frequencies in the modem's usable band(s).

Abstract: An improved discrete multi-tone transmission scheme is describe that contemplates encoding digital data and modulating the encoded data onto a discrete multi-tone signal having a total bandwidth of at least 1.6 MHz. In some embodiments bandwidths of 8 MHz or more are provided. The modulation system is capable of dynamically updating the subcarriers used and the amount of data transmitted on each subcarrier during transmission in order to accommodate real time changes in the line quality over particular subcarriers. In one preferred embodiment of the invention the multi-tone encoding and modulation is done in substantial compliance with the ATIS North American Asymmetric Digital Subscriber Lines standard. However, additional subchannels (such as a total of 512 subchannels) may be used and/or subchannel bandwidths of greater than 4.3125 kHz may be used.

Abstract: An improvement in the preparation of printed circuits comprises inserting a deformable layer between the phototool or support layer, and the solder mask. The deformable layer provides a uniform, integral and relatively thin coating of solder mask over circuit components, and results in higher-quality solder joints and lower rejection rates for finished boards.