Ikanos Communications Patent Grants

Methods and apparatuses for characterizing common mode noise and estimating loop imbalance

Granted: February 7, 2017
Patent Number: 9564946
The present invention relates generally to addressing performance issues in xDSL communication systems, and more particularly to methods and apparatuses to measure and characterize CM noise impacting a DSL line in a customer premises, measurements and characterization of the projection of these CM signals in Differential Mode (DM), and finally a derivation of an estimate of the loop balance.

Reduced precision vector processing

Granted: February 7, 2017
Patent Number: 9565048
Methods, systems, and devices are described for wired communication. In one aspect, a method includes selecting a gain scalar based at least in part on a constellation point distance associated with a constellation mapper for a line and a tone. The method also includes applying the gain scalar to a tone data output signal of a vector processor.

Method and apparatus for managing joining events for G.fast vectoring with discontinuous operation

Granted: November 29, 2016
Patent Number: 9509518
In general, the present invention provides an efficient usage of Far End Crosstalk (FEXT) coefficient memory in a G.fast vectoring system. According to certain aspects, embodiments of the invention provide a simple scheme for efficient management of the Discontinuous (DO) and Regular Operation (RO) FEXT coefficient memories to handle the complexity of lines joining/leaving the system in both regular and DO groups. In embodiments, by disabling the power-efficient, Discontinuous Operation,…

Reduced memory vectored DSL

Granted: November 8, 2016
Patent Number: 9490872
A reduced-memory vectored DSL system reduces the bandwidth and memory storage demands on a vectored DSL system in which FEXT data is transmitted and stored. When test signal data, such as training and/or tracking data, is sent to determine FEXT characteristics of the DSL system, error signals are available for all or substantially all of the upstream and/or downstream frequency band DSL tones used in the system. Dividing a frequency band into sub-bands, only a subset of tones in each…

Method and apparatus for initiating and data collection of single ended line test on customer premises equipment

Granted: October 4, 2016
Patent Number: 9461704
According to certain aspects, embodiments of the invention relate to methods and apparatuses for performing diagnostics on a loop in a communications system. According to certain aspects, embodiments of the invention include performing SELT from a customer premises side of the loop. According to certain other aspects, embodiments of the invention address the issue of initiating a CPE side SELT procedure and also collecting the diagnostics data while a CPE is offline.

Method and apparatus for detecting missing micro-filter

Granted: August 30, 2016
Patent Number: 9432493
The present invention provides a method and apparatus to detect a missing micro-filter. In embodiments, the detection is performed by measuring the distortion caused by an unfiltered telephone device using a SELT (Single Ended Line Test) technique. According to certain aspects, the signal used to perform the distortion measurement is designed such that it causes minimal impact on vectored lines within the same cable. Embodiments of the invention first determines the estimated loop…

UPBO for vectored DSL

Granted: August 23, 2016
Patent Number: 9425858
Residual FEXT resulting from intended and/or inherent partial cancellation of crosstalk in vectored DSL systems impairs upstream power back-off (UPBO) as traditionally implemented. By considering and taking into account the effects of residual crosstalk on vectored DSL system performance and operation, improved data rates and/or other vectored DSL system performance are realized through the use of UPBO parameters generated for a given residual FEXT environment.

Method and apparatus for gauge identification based on single ended line testing (SELT)

Granted: August 23, 2016
Patent Number: 9426268
The present invention relates generally to characterizing loops in a communication system, and more particularly to methods and apparatuses for loop gauge identification. In accordance with certain aspects, embodiments of the invention extract some information from the SELT signal. From SELT, the loop impedance, or equivalently input impedance, is determined. This information is then used for gauge identification.

Method and apparatus of optimizing an xDSL transceiver configuration using single ended line test (SELT) measurement

Granted: August 23, 2016
Patent Number: 9426283
The present invention relates to a method by which an xDSL modem can be properly connected and/or optimally tuned to achieve a desired performance goal based on knowledge obtained by first performing a SELT test and then post-processing the results of that test. In embodiments, the processed SELT results are used to detect bad connections or other anomalies such as split pairs. In embodiments, the processed SELT results are used to configure programmable components and filters in the…

Method and apparatus for sensing noise signals in a wireline communications environment

Granted: August 9, 2016
Patent Number: 9413424
The present invention relates to methods and apparatuses for sensing noise sources in a wireline communications environment such as a customer premises environment in a DSL system. In embodiments, the invention includes an additional sensor that is connected to power mains in a DSL customer premises environment either to characterize, at their source, noises coupling into the DSL lines, and/or to mitigate their impact into the DSL lines. One objective is associated with diagnostics that…

Method and apparatus for improving performance of transmit controlled adaptive modulation in xDSL and G.fast systems

Granted: July 19, 2016
Patent Number: 9397781
According to certain aspects, the present invention improves upon the conventional TCAM scheme by allowing a traditional TCM scheme to be used while in RCM mode. In a RCM mode according to embodiments of the invention, the system uses traditional TCM+SNR margin (i.e. SNRM) with a receiver controlled bit allocation table (BAT) and tone ordering table (TOT). In a TCAM mode according to embodiments of the invention, the system uses uncoded hierarchical modulation similar to the modulation…

Method and apparatus for detecting and analyzing noise and other events affecting a communication system

Granted: July 5, 2016
Patent Number: 9385780
The present invention generally relates to a method and apparatus for effectively detecting and characterizing noise and other events affecting a communications system such as digital subscriber lines (DSL). According to certain aspects, the invention includes a noise analysis engine that is embedded in customer premises equipment that classifies noise sources according to their specific characteristics and tracks each noise source in a dynamic manner, in such a way as to provide…

Methods and apparatuses for characterizing common mode noise and estimating loop imbalance

Granted: July 5, 2016
Patent Number: 9385781
The present invention relates generally to addressing performance issues in xDSL communication systems, and more particularly to methods and apparatuses to measure and characterize CM noise impacting a DSL line in a customer premises, measurements and characterization of the projection of these CM signals in Differential Mode (DM), and finally a derivation of an estimate of the loop balance.

Method and apparatus for performing multi-symbol rate vectoring

Granted: June 7, 2016
Patent Number: 9362982
The present invention is directed to methods and apparatuses for performing concurrent vectoring of systems having communications performed at different symbol rates. In embodiments, where a common binder includes different sub-groups of lines having corresponding different symbol rates, the invention includes methods and apparatuses for managing and concurrently vectoring all the lines of the different sub-groups.

Method and apparatus for detecting and locating loop impairments

Granted: May 10, 2016
Patent Number: 9338281
According to certain aspects, the present invention relates to methods and apparatuses to identify and locate a line-cuts in a loop that may or may not also contain bridgetaps. In embodiments, different bands of SELT signal data are analyzed separately using a TDR method, to effectively detect any potential bridgetaps. In these and other embodiments, by combining information from the separate bands, bridgetap locations and lengths are determined. Methodology is also established to…

Systems and methods for G.vector initialization

Granted: February 23, 2016
Patent Number: 9270831
Methods, apparatuses (e.g., DSL system hardware, DSL systems, vectoring control entities), techniques, systems, etc. are used for initializing one or more DSL lines joining a vectored DSL line group operating in Showtime. A super-periodic orthogonal pilot sequence from a set of super-periodic orthogonal pilot sequences is assigned to each joining DSL line, wherein each such super-periodic orthogonal pilot sequence in the set has length L and is orthogonal to other sequences in the set…

Systems and methods for implementing a multi-sensor receiver in a DSM3 environment

Granted: November 10, 2015
Patent Number: 9184774
In accordance with one embodiment, a method is implemented in a vectored system for improving a signal-to-noise ratio (SNR) of a far end transmitted signal on a victim line in the system. The method comprises mitigating, by the vectored system, self-induced far-end crosstalk (self-FEXT) on the victim line based on self-FEXT mitigation coefficients and receiving, by a second sensor, information relating to at least one of: self-FEXT of the vectored system, external noise, and the far end…

Method and apparatus for designing an improved transmit signal for use in a single ended line test (SELT)

Granted: November 10, 2015
Patent Number: 9185204
The present invention relates to methods and apparatuses of using a novel transmit signal that can be used to improve performance of various loop diagnostic features of SELT. In embodiments, a novel transmit signal uses a wide contiguous band of tones that includes frequencies in both upstream and downstream bands. In these and other embodiments of the invention, the SELT transmit signal is designed such that any crosstalk noise in adjacent lines appears as a burst of noise that falls…

Method and apparatus for detecting improper connections near a customer premises equipment

Granted: November 3, 2015
Patent Number: 9178668
Methods and apparatuses are disclosed for detecting improper connection near the end of an xDSL loop based on separately analyzing the location and levels of time domain signals associated with different transmission bands in an xDSL band plan. In one embodiment, a method is disclosed to separately convert the received test signal data to different sets of time domain data corresponding to different sets of the separate frequency bands, and then to separately analyze the different sets…

Systems and methods for characterizing loops based on single-ended line testing (SELT)

Granted: November 3, 2015
Patent Number: 9178990
Systems and methods for characterizing loops based on frequency domain reflectometry single-ended line testing (FDR-SELT) are described. One embodiment includes a method for determining whether a straight-loop departure condition exists on a loop under test. First, an un-calibrated echo signal is received. A region associated with the loop under test, a platform type, and estimated the length of the loop under test are then used together with the received un-calibrated echo signal to…