Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B17/00—Monitoring; Testing
  • H04B17/30—Monitoring; Testing of propagation channels
  • H04B17/309—Measuring or estimating channel quality parameters
  • H04B17/336—Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B3/00—Line transmission systems
  • H04B3/02—Details
  • H04B3/46—Monitoring; Testing
  • H04B3/48—Testing attenuation
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
  • H04L41/06—Management of faults, events, alarms or notifications
  • H04L41/0631—Management of faults, events, alarms or notifications using root cause analysis; using analysis of correlation between notifications, alarms or events based on decision criteria, e.g. hierarchy, tree or time analysis
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
  • H04L41/06—Management of faults, events, alarms or notifications
  • H04L41/0677—Localisation of faults
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M3/00—Automatic or semi-automatic exchanges
  • H04M3/08—Indicating faults in circuits or apparatus
  • H04M3/085—Fault locating arrangements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M3/00—Automatic or semi-automatic exchanges
  • H04M3/22—Arrangements for supervision, monitoring or testing
  • H04M3/26—Arrangements for supervision, monitoring or testing with means for applying test signals or for measuring
  • H04M3/28—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor
  • H04M3/30—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop
  • H04M3/302—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop using modulation techniques for copper pairs
  • H04M3/304—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop using modulation techniques for copper pairs and using xDSL modems
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M3/00—Automatic or semi-automatic exchanges
  • H04M3/22—Arrangements for supervision, monitoring or testing
  • H04M3/26—Arrangements for supervision, monitoring or testing with means for applying test signals or for measuring
  • H04M3/28—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor
  • H04M3/30—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop
  • H04M3/305—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop testing of physical copper line parameters, e.g. capacitance or resistance
  • H04M3/306—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop testing of physical copper line parameters, e.g. capacitance or resistance for frequencies above the voice frequency, e.g. xDSL line qualification
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/2854—Wide area networks, e.g. public data networks
  • H04L12/2856—Access arrangements, e.g. Internet access
  • H04L12/2869—Operational details of access network equipments
  • H04L12/2898—Subscriber equipments
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/64—Hybrid switching systems
  • H04L12/6418—Hybrid transport
  • H04L2012/6478—Digital subscriber line, e.g. DSL, ADSL, HDSL, XDSL, VDSL
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M2201/00—Electronic components, circuits, software, systems or apparatus used in telephone systems
  • H04M2201/12—Counting circuits

Definitions

• One exemplary purpose of certain embodiments of this invention is to detect the presence of one or more faults that affect DSL communications, and upon their detection, generate, for example, a message that recommends corrective action.
• a fault is one or more unfiltered devices, impulsive noises, malfunctioning modems, or something else that does not affect measured attenuation or measured noise but does affect the signal-to-noise ratio of the link.
• DSL Digital Subscriber Line
• Another exemplary purpose of this invention is to estimate the rate impact of the detected fault.
• One aspect of the invention is to detect the presence of one or more faults that affect DSL communications, and upon their detection, generate, for example, an indication, communication or message that recommends corrective action.
• a fault is generally caused by one or more unfiltered devices, impulsive noises, malfunctioning modems, any non-linearity on the line, any noise source that is not present when the SNR is measured, or any or other factor that does not affect measured attenuation or measured noise, but does affect the signal-to-noise ratio (SNR) of the link.
• SNR signal-to-noise ratio
• Additional aspects of the invention relate to multi-carrier communications links, such as discrete multi-tone (DMT).
• DMT discrete multi-tone
• One exemplary method may use standard- compliant links (i.e., as specified in published DSL standards such as ITU-T G.992.3/5 and G.993.2, which are incorporated herein by reference in their entirety), but it is not restricted to standard compliant links.
• Other embodiments of this invention can apply to single-carrier communications links.
• the individual carriers used for the link will be referred to as "subchannels.”
• subchannels For a multi-carrier communications system, there will be multiple subchannels, whereas for a single-carrier communications system there would be only one subchannel.
• each link is full duplex, including both an upstream (US) direction and a downstream (DS) direction.
• US upstream
• DS downstream
• a power spectral density (PSD) is transmitted in both directions during a communications link.
• SNRs signal-to-noise ratios
• ITU DSL standards ADSL2/2+, VDSL2, G.inp, etc.
• MIB Management Interface
• Showtime which is term used to denote the steady-state data transmission mode for DSL.
• a management interface e.g. MIB
• the measured per-subchannel SNRs, measured per-subchannel HLOG, measured per- subchannel QLN, and information describing the link such as transmit PSD, DSL standard and link parameters.
• ModeledSNR (TxPSD * HLOG) / (QLN + IntrinsicNoise), where TxPSD, HLOG, and QLN are each understood to be given on a per-subchannel basis, and IntrinsicNoise is a per-subchannel noise model that encapsulates the noise arising from the modems (e.g., thermal noise floors) and signal propagation and processing (e.g., intersymbol interference, echo, and quantization effects).
• modems e.g., thermal noise floors
• signal propagation and processing e.g., intersymbol interference, echo, and quantization effects
• IntrinsicNoise is generally dependent upon HLOG, QLN, and the modem types. It can be characterized in advance of the system being deployed and pre- stored for use when the system is operational.
• One exemplary brute-force approach to implementing the intrinsic noise model is simply to construct a lookup table for each condition that could be encountered in the field.
• one or more models can be constructed to approximate the behavior of IntrinsicNoise for different combinations of conditions.
• a simple approximate model of the intrinsic noise such as white noise, may be used in some cases. The effects of intrinsic noise may be neglected if they are insignificant relative to the QLN.
• pre-stored correction factors may need to be applied to the
• MeasuredSNR / ModeledSNR ⁇ SNRThreshold is some reasonable ratio that allows for modeling and measurement errors to occur without a tolerable rate of false fault detections and missed fault detections.
• FaultAttenuation MeasuredSNR / ModeledSNR, which can be compared directly with SNRThreshold. Therefore, FaultAttenuation analysis is equivalent to comparing the modeled and measured SNRs.
• the analysis may be performed by estimating the noise amplification apparently attributable to the fault (denoted NoiseAmplification), which can be inferred from the SNR values by assuming knowledge of the noise values, transmitted PSD, and the received signal.
• denoted NoiseAmplification the noise amplification apparently attributable to the fault
• an exemplary method would replace steps 3 and 4 above with the following steps:
• NoiseAmplification ⁇ NoiseAmplificationThreshold, where NoiseAmplificationThreshold is some reasonable differential that allows for modeling and measurement errors to occur without a tolerable rate of false fault detections and missed fault detections.
• NoiseAmplification ModeledSNR / MeasuredSNR, which can be compared with 1/SNRThreshold. Therefore, NoiseAmplification analysis is equivalent to comparing the modeled and measured SNRs.
• a confidence metric can be formulated that quantifies the extent to which it is known that a fault is present on the line. This can be formulated in terms of a probability given the information that is known, or some other metric that is informative to the user. [0028] Note that the proposed method can be used as a form of "domain location,” which is to say that it narrows down the probability that a particular problem occurs within some part of the network (e.g., inside the customer premises, inside the central office, or in the cables in the field). Given that a fault is detected, the probability that the fault occurs in a specific domain can be conditioned on information about the prevalence of unfiltered devices, impulse noise, malfunctioning hardware, etc.
• a module capable of detecting the presence of a fault by comparing the modeled SNR with the measured SNR for a given link, wherein the modeled SNR is derived from one or more of the measured HLOG, measured QLN, transmit PSD, DSL standard, link parameters, and known modem behavior, and the measured SNR is reported by a modem.
• a method for detecting the presence of a fault comprising: comparing the modeled SNR with the measured SNR for a given link, wherein the modeled SNR is derived from one or more of the measured HLOG, measured QLN, transmit PSD, DSL standard, link parameters, and known modem behavior, and the measured SNR is reported by a modem.
• a computer-readable information storage media having stored thereon instructions that, if executed, cause comparing of a modeled SNR with a measured SNR for a given link, wherein the modeled SNR is derived from one or more of the measured HLOG, measured QLN, transmit PSD, DSL standard, link parameters, and known modem behavior, and the measured SNR is reported by a modem.
• a method of detecting the presence of a fault comprising: comparing the modeled data rate with the measured data rate for a given link, wherein the modeled data rate is derived from one or more of the measured HLOG, measured QLN, transmit PSD, DSL standard, link parameters, and known modem behavior, and the measured data rate is reported by a modem.
• a computer-readable information storage media having stored thereon instructions that, if executed, cause comparing of a modeled data rate with a measured data rate for a given link, wherein the modeled data rate is derived from one or more of the measured HLOG, measured QLN, transmit PSD, DSL standard, link parameters, and known modem behavior, and the measured data rate is reported by the modem.
• a method of detecting the presence of a fault comprising: determining the significance of the additive noise apparently attributable to the fault relative to the other known noises, wherein the apparent fault noise is derived from one or more of the measured SNR, measured HLOG, measured QLN, transmit PSD, DSL standard, link parameters, and known modem behavior.
• a computer-readable information storage media having stored thereon instructions that, if executed, cause determining of the significance of the additive noise apparently attributable to the fault relative to the other known noises, wherein the apparent fault noise is derived from one or more of the measured SNR, measured HLOG, measured QLN, transmit PSD, DSL standard, link parameters, and known modem behavior. 15. Aspect 12 or 13 orl4, wherein the apparent fault noise is derived from one or more of an SNR measurement, attenuation measurement, a noise measurement, knowledge about the link parameters such as transmitted PSD, and the behavior of the modems.
• a module capable of detecting the presence of a fault by determining the significance of the attenuation apparently attributable to the fault, wherein the apparent fault attenuation is derived from one or more of the measured SNR, measured HLOG, measured QLN, transmit PSD, DSL standard, link parameters, and known modem behavior.
• a method of detecting the presence of a fault comprising: determining the significance of the attenuation apparently attributable to the fault, wherein the apparent fault attenuation is derived from one or more of the measured SNR, measured HLOG, measured QLN, transmit PSD, DSL standard, link parameters, and known modem behavior.
• a computer-readable information storage media having stored thereon instructions that, if executed, cause determining of the significance of the attenuation apparently attributable to the fault, wherein the apparent fault attenuation is derived from one or more of the measured SNR, measured HLOG, measured QLN, transmit PSD, DSL standard, link parameters, and known modem behavior.
• a method of detecting the presence of a fault comprising: determining the significance of the noise emphasis apparently attributable to the fault, wherein the apparent fault noise emphasis is derived from one or more of the measured SNR, measured HLOG, measured QLN, transmit PSD, DSL standard, link parameters, and known modem behavior.
• a computer-readable information storage media having stored thereon instructions that, if executed, cause the determining of the significance of the noise emphasis apparently attributable to the fault, wherein the apparent fault noise emphasis is derived from one or more of the measured SNR, measured HLOG, measured QLN, transmit PSD, DSL standard, link parameters, and known modem behavior.
• One exemplary embodiment of the proposed method can utilize standard compliant data collection. This includes ITU and ANSI DSL standards. Because it is possible (although not necessary) to utilize standard-compliant DSL links to acquire the data rather than relying on a proprietary implementation that might not be implemented on some modems, more modems can utilize the proposed method because the vast majority of DSL modems are effectively standard compliant.
• One exemplary embodiment of the proposed method can utilize standard compliant sending of data from the far-end modem to the central office, which enables data collection to be initiated and results made available remotely (e.g., from a central office far from the CPE modem and unfiltered devices) without requiring a commutations channel other than the DSL link itself used to perform the measurement.
• FIG. IA illustrates an exemplary communications system according to this invention
• Fig. IB illustrates a second exemplary communications system that includes a diagnostic interface according to this invention
• FIG. 2 illustrates an exemplary method of detecting and correcting faults according to this invention
• FIG. 3 illustrates an exemplary method of fault detection based on SNR according to this invention

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• Engineering & Computer Science (AREA)
• Signal Processing (AREA)
• Computer Networks & Wireless Communication (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Quality & Reliability (AREA)
• Telephonic Communication Services (AREA)
• Maintenance And Management Of Digital Transmission (AREA)

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• 2009
  • 2009-11-24 CA CA2744040A patent/CA2744040A1/en active Pending
  • 2009-11-24 US US13/128,049 patent/US8611405B2/en active Active
  • 2009-11-24 EP EP09760432.6A patent/EP2366235B1/de active Active
  • 2009-11-24 WO PCT/US2009/065740 patent/WO2010060086A1/en active Application Filing
• 2011
  • 2011-11-01 HK HK11111773.7A patent/HK1157532A1/xx not_active IP Right Cessation
• 2013
  • 2013-11-27 US US14/092,484 patent/US8743938B2/en not_active Expired - Fee Related
• 2014
  • 2014-05-23 US US14/286,710 patent/US9054794B2/en active Active

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