Abstract: The measurement of far-end crosstalk (FEXT) in a Digital Subscriber Line communications is instrumental in the ability of using a multiple input multiple output (MIMO) pre-coder to cancel FEXT. A reliable robust back channel for transmission of error is instrumental to provide error samples for the proper operation of a MIMO pre-coder. Bins can be dedicated to insure bandwidth from the customer premises equipment (CPE) to the central office (CO). By increasing the margin used in the bins, robustness can be added to this back channel between the CPE and CO.

Abstract: Included are embodiments of method for method for computing metrics. At least one embodiment includes searching a MIMO detection tree, the detection tree configuration being formed by a plurality of nodes and a plurality of leaves connected via a plurality of branches, the computational complexity associated with computing a node metric decreases with the node depth in the tree configuration and providing an estimate on a transmitted signal.

Abstract: The present invention overcomes various problems by defining two upstream masks (U1, U2) and two downstream masks (D1, D2) and using a mask selectable system for the long reach digital subscriber line (LDSL), in which a unique modem feature is activated during handshake to automatically check for physical layer status in terms of spectral compatibility and, thus, automatically optimize the boosted mode with the use of the mask selectable system choose the best combination of upstream/downstream masks in any physical layer noise scenario.

Abstract: Systems and methods for deriving parameters for frequency domain impulse noise detectors are described. At least one embodiment is a method for deriving a set of parameters associated with a frequency domain impulse noise detector. In accordance with such embodiments, the method comprises setting values for ?pivot and ?c, wherein ?pivot and ?c are values associated with a monotonic function of a ratio of a statistical parameter of disruptive noise to a statistical parameter of nominal noise. The method further comprises selecting a fixed ratio (m/M), wherein M is a number of monitored tones, and wherein m is a number of slicer error samples that must exceed a decision threshold for a symbol to be flagged as corrupted.

Abstract: A technique for dynamic bin allocation is disclosed. In one particular exemplary embodiment, the technique may be realized as a method for dynamic bin allocation. The method may comprise obtaining link performance data based on a plurality of test transmissions between two network elements, wherein the plurality of test transmissions utilize at least one transmission mode in each of a plurality of frequency ranges. The method may also comprise determining a desired transmission scheme, wherein each of the plurality of frequency ranges is designated for at least one of the at least one transmission mode based at least in part on the link performance data. The desired transmission scheme may be determined by identifying a desired transmission mode for each of the plurality of frequency ranges, or the desired transmission scheme may be selected from a plurality of predetermined transmission schemes.

Abstract: Impulse noise from nearby or intense electrical sources can disrupt communications over digital subscriber lines. There are many methods to deal with errors produced by impulse noise sources. Forward error correction (FEC) codes such as Reed Solomon coding along with scrambling and interleaving are used to correct small errors. However, for larger errors, retransmission is favored. Retransmission can be applied at the Discrete Multi-tone symbol level thus eliminating the need to insert sequence identification into data transmission units, furthermore retransmission can also be employed to exploit the error correcting capabilities of the FEC codes. Finally, an impulse noise protection system can exploit impulse noise statistics to configure the redundancy in the FEC codes and to enable the use of blanking. Exemplary embodiments of systems described can cooperatively use impulse noise statistics to utilize retransmission, FEC and blanking to mitigate the effects of impulse noise.

Abstract: Method and System for evaluating a turbo-coding scheme suitable for VDSL2 systems. The scheme is a Turbo-Trellis Coded Modulation TTCM that makes use of a Parallel Concatenated Convolutional Code (PCCC) including an inner Latin square/rectangular matrix of Random sequence pattern Interleaver (LRI) of approximately 2044 bits. In the presence of the outer Reed Solomon Code but without an outer interleaver (fast mode), the method and system provides 7.1 dB of average net coding gain, i.e., 2.6 dB of coding gain improvement relative to the standard 16 states 4-dimensional (4-D) trellis code used in current ADSL2 systems. The substantial coding gain achieved through the method and system, leads to an increase in the VDSL2 rate by 38% at 6 kft against local exchange carriers, such as ILEC (SBC) conditions with approximately 1.5 ms of latency. By encoding only two bits per tone (i.e., 1 bit per dimension), the turbo code implementation complexity is kept reasonable.

Abstract: Systems and methods for mitigating the effects of self-FEXT within an xDSL system are described. At least one embodiment is a method for reducing self-induced far end crosstalk (self-FEXT) in a multiple input multiple output (MIMO) digital subscriber line (xDSL) system. The method comprises deriving an initial value for an off-diagonal multiple input multiple output canceller (ODMC) while the ODMC is inactive and while in data mode. The method further comprises activating the initial ODMC and converging towards an steady-state value for the ODMC by performing an adaptive algorithm to maximize the Shannon's capacity of the system and to reduce upstream self-FEXT. The method also comprises performing bit loading and updating a frequency domain equalizer (FEQ).

Abstract: The present invention overcomes various problems by defining two upstream masks (U1, U2) and two downstream masks (D1, D2) and using a mask selectable system for the long reach digital subscriber line (LDSL), in which a unique modem feature is activated during handshake to automatically check for physical layer status in terms of spectral compatibility and, thus, automatically optimize the boosted mode with the use of the mask selectable system choose the best combination of upstream/downstream masks in any physical layer noise scenario.

Abstract: Systems and methods for reducing the peak-to-average power ratio (PAR) at the transmitter can reduce the dynamic range required in various analog components. PAR can be reduced by applying a time-domain compensation signal in the oversampled regime, using tones reserved for PAR reduction. A set of vectors corresponding to PAR tones is generated by processing out-of-phase symbols for each PAR tone to form a span matrix. The span matrix is used to find a best fit of a desired target signal to a time-domain compensation signal comprising only PAR tones.

Abstract: Systems and methods for performing loop length estimation are described. One embodiment includes a method which comprises receiving an echo signal for a loop under test where the echo signal is a per-port calibrated echo response obtained using frequency domain reflectometry single-ended line testing (FDR-SELT). The method further comprises analyzing characteristics of the echo signal to perform a loop length estimation based on data relating to ripple frequency as a function of loop length.

Abstract: A method and apparatus for single end loop testing for DSL provisioning and maintenance provides testing of the DSL loop using digital techniques including frequency compensation, matched filtering and median filtering, to remove strong background and enhance desired signal for peak detection. The SELT system allows DSL providers to extract loop information from reflective measurements at the central office (CO) so as to determine loop capability of supporting different DSL services. The method and apparatus acquires the desired signal (the far-end echo) which is submerged in the correlated background noise (the near-end echo) by providing a process for detecting loop length and termination types with high accuracy for loops up to 12 kft for 24 AWG and up to 9 kft for 26 AWG by exploiting several digital signal processing techniques including frequency.

Abstract: Disclosed herein are various techniques for multilevel channel coding. For a given binary word comprising a plurality of bits, the least-significant bit may be encoded by a boosted coding technique, such as turbo channel coding or low density parity check (LDPC) channel coding. A subset of the remaining bits of the binary word may be encoded using trellis coded modulation (TCM) coding. The results of the boosted channel coding and the TCM coding may be mapped to one or more symbols. The one or more symbols then may be transmitted to a receiver using transmission techniques well known to those skilled in the art. The present invention finds particular benefit in digital subscriber line (DSL)-based systems in accord with the ITU G.922.1 Recommendation and similar standards.

Abstract: The present invention is directed to implementing theoretical foundations of frequency domain methods aiming to locally decrease the impact of aggregate side lobes of a few discrete frequency tones, in the vicinity of other “victim” frequencies. The family of frequency methods referred to makes use of one or more “canceller tones.” The “canceller tones” loads are optimized to minimize the aggregate power in the neighborhood of the victim frequencies.

Abstract: Systems and methods for performing loop termination are described. One embodiment is a method that comprises receiving a per-port calibrated echo signal of a loop under test, receiving a region designation and a loop length for the loop under test, and determining whether the loop is terminated by a short or open termination based on phase of the per-port calibrated echo signal.

Abstract: A telecommunication receiver provided according to the present invention is implemented to receive a first signal containing information and noise on a first set of sensors and a second signal containing only noise on a second set of sensors. Receiver then decodes the information using first signal and second signal. In one embodiment, a bonded DSL receiver with k signals sensors is implemented with additional s number of noise only sensors to receive only noise. Accordingly, joint demodulation is performed using signals received on k signals sensors and s noise only sensors. The noise sensor is implemented in common mode.

Abstract: Crosstalk interference induced by the adjacent pairs is one of the major performance limiting factors of DSL systems. As there is a rapid increase in the deployment of DSL services worldwide, the need to provide information about noise related parameters to the operators and the service providers is of utmost importance. Satisfying such a need enables operators to anticipate the line capacity and understand the noise level characteristics of the loop environment. Specifically, crosstalk and more particularly upstream near end crosstalk (NEXT) in the presence of narrowband interference can be classified to isolate the particular service type causing the upstream NEXT. The identification of the service type of the upstream NEXT would enable operators to address the disturber.

Abstract: Included are embodiments for back channel communication. At least one embodiment of a method includes receiving data at customer premises equipment and determining at least one error in the received data. Some embodiments include formatting the determined error for communication to a central office and sending the formatted error to the central office via a back channel.

Abstract: Systems and methods for performing bridge tap detection are described. One embodiment is a method which comprises receiving an echo signal for a loop under test where the echo signal is a per-port calibrated echo response obtained using frequency domain reflectometry single-ended line testing (FDR-SELT). The method further comprises analyzing the echo signal to determine whether differentiating features are present in the per-port calibrated echo signal in order to determine whether the loop under test is a bridge tapped loop.

Abstract: Systems and methods for performing loop gauge detection are described. One embodiment is a method that comprises receiving a calibrated per-port echo signal of a loop under test, receiving a loop length estimation for the loop under test, and estimating the loop gauge of the loop under test if the loop is not determined to be a long loop based on a predetermined threshold and if no bridge tap is present on the loop. In accordance with such embodiments, estimating the loop gauge of the loop under test is based on at least one of the following echo signal features: energy of the echo signal in a predetermined frequency band, information on an envelope of maxima for the echo signal, information on an envelope of minima for the echo signal, and a span of ripples on the amplitude of the echo signal.