WO2017219318A1 - 一种cm和hfc网络故障定位系统及故障检测方法 - Google Patents

一种cm和hfc网络故障定位系统及故障检测方法 Download PDF

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Publication number
WO2017219318A1
WO2017219318A1 PCT/CN2016/086898 CN2016086898W WO2017219318A1 WO 2017219318 A1 WO2017219318 A1 WO 2017219318A1 CN 2016086898 W CN2016086898 W CN 2016086898W WO 2017219318 A1 WO2017219318 A1 WO 2017219318A1
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WO
WIPO (PCT)
Prior art keywords
uplink signal
signal
uplink
upstream
duplexer
Prior art date
Application number
PCT/CN2016/086898
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English (en)
French (fr)
Inventor
张小龙
欧阳涛
张利
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华为技术有限公司
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Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to PCT/CN2016/086898 priority Critical patent/WO2017219318A1/zh
Publication of WO2017219318A1 publication Critical patent/WO2017219318A1/zh
Priority to US16/230,100 priority patent/US10630383B2/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
    • H04B10/0791—Fault location on the transmission path
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
    • H04B10/0795—Performance monitoring; Measurement of transmission parameters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2575—Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
    • 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]
    • H04L12/2801—Broadband local area networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/60—Network structure or processes for video distribution between server and client or between remote clients; Control signalling between clients, server and network components; Transmission of management data between server and client, e.g. sending from server to client commands for recording incoming content stream; Communication details between server and client 
    • H04N21/61—Network physical structure; Signal processing
    • H04N21/6156—Network physical structure; Signal processing specially adapted to the upstream path of the transmission network
    • H04N21/6168—Network physical structure; Signal processing specially adapted to the upstream path of the transmission network involving cable transmission, e.g. using a cable modem

Definitions

  • the present invention relates to the field of communications technologies, and in particular, to a cable modem (Cable Modem, abbreviated as: CM) and a Hybrid Fiber-Coaxial (HFC) network fault location system and a fault detection method.
  • CM Cable Modem
  • HFC Hybrid Fiber-Coaxial
  • HFC network technology is an economical and practical integrated digital service broadband network access technology.
  • HFC usually consists of three parts: optical fiber trunk, coaxial cable branch and user wiring network.
  • the program signal from the cable TV station first becomes the optical signal transmitted on the trunk line; after the user area, the optical signal is converted into an electrical signal.
  • the distributor is finally distributed to the user via a coaxial cable.
  • Figure 1 shows a typical HFC network.
  • the HFC network can include the following devices and devices: Network Management System, Metropolitan Area Network, and Cable Modem Terminal System (CMTS). ), optical station, CM, set-top box (STB) on the user side, personal computer (PC) and fiber, coaxial cable, amplifier, splitter (Tap) And so on, the individual devices are not shown one by one in FIG.
  • CMTS Network Management System
  • CMTS Cable Modem Terminal System
  • STB set-top box
  • PC personal computer
  • fiber coaxial cable
  • amplifier splitter
  • DOCSIS Data Over Cable Service Interface Specifications
  • CMTS complementary metal-oxide-semiconductor
  • CMTS complementary metal-oxide-semiconductor
  • the uplink signal can be measured along the upstream channel, the sudden change of the uplink signal degradation can be analyzed to find the fault location.
  • the detection of the uplink signal can be implemented at the CM.
  • the prior art proposes a method for extending the full spectrum scanning (Full Band Capture, FBC) function of the CM to the uplink.
  • FBC Full spectrum scanning
  • the simplified implementation of the method is shown in Figure 2. It leads a branch in front of the duplexer (ie, the "1" point in Figure 2), and the other end of the branch is connected to the front of the downstream FBC module ( Figure 2).
  • the Analog-to-Digital Converter (ADC) in the FBC module can collect the uplink noise for the uplink noise analysis. This allows the CM to have upstream noise acquisition and upstream noise detection.
  • ADC Analog-to-Digital Converter
  • the CM that uses the downlink FBC function to detect the uplink signal can generally detect only two types of infinite noise types such as intrusion noise and white noise in the uplink signal, and cannot detect other fault problems.
  • the embodiments of the present invention provide a CM and HFC network fault location system and a fault detection method, which are used to solve the problem that the existing CM can only detect two kinds of limited noise types such as intrusion noise and white noise outside the carrier.
  • CM includes an acquisition module and an analysis module:
  • the collecting module collects an uplink signal from a downstream of the CM, or collects an uplink signal from an upstream of the CM, or collects an uplink signal that is mixed from upstream and downstream of the CM;
  • the analysis module detects whether the uplink signal has at least one of intrusion noise, white noise, nonlinear distortion, impulse noise, intrusion noise under the carrier, and linear distortion.
  • the solution provided by the present application transforms the conventional CM, so that the CM can not only detect intrusion noise and white noise outside the carrier, but also detect other faults such as nonlinear distortion, impulse noise, intrusion noise under the carrier, and linear distortion.
  • the acquisition module may have the following three acquisition modes when collecting the uplink signal:
  • the first type the time interval corresponding to the empty time slot or the silence detection signal is determined according to the uplink bandwidth allocation mapping message sent by the CMTS, and the uplink signal is collected in the time interval corresponding to the empty time slot or the silence detection signal,
  • the uplink bandwidth allocation mapping message message is used to indicate a time slot occupied by each CM under the jurisdiction of the CMTS, and the empty time slot or silence detection signal indicates that it is not allowed to be used.
  • the uplink signal is randomly collected.
  • the detecting module when detecting whether the uplink signal has nonlinear distortion, specifically includes:
  • the uplink signal has nonlinear distortion.
  • the acquisition module further includes a band pass filter, the acquisition module collects the uplink signal after passing the band pass filter; or the acquisition module collects the uplink signal and then The collected uplink signal is input to the band pass filter for processing; the center frequency of the band pass filter is outside the uplink working frequency band of the CM;
  • the detecting module when detecting whether the uplink signal has impulse noise, specifically includes:
  • the collecting module collects the uplink signal in a time interval corresponding to the empty time slot or the silent detection signal
  • the analysis module is specifically configured to:
  • the collecting module collects the uplink signal, it is determined by spectrum analysis whether the uplink signal has intrusion noise under the carrier.
  • the collecting module collects the uplink signal in a time interval corresponding to the SID of any one of the devices;
  • the analysis module is specifically configured to:
  • the analysis module is also used to:
  • test signal is the uplink signal from the The initial status signal when any device is sent.
  • the CM further includes an interface, an uplink sending module, a downlink receiving module, and a duplexer;
  • the duplexer is connected to the interface, and a low pass filter in the duplexer is connected to the uplink sending module, and a high pass filter in the duplexer is connected to the downlink receiving module;
  • the acquisition module and the analysis module are located on a branch of a line between the duplexer and the interface; or the acquisition module and the analysis module are located in the duplexer and the uplink sending module On the branch between the lines.
  • the structure of the above CM is mainly applied to a frequency division system.
  • the CM further includes an interface, an uplink sending module, a downlink receiving module, and a circulator;
  • the three ports of the circulator are respectively connected to the interface, the uplink sending module, and the downlink receiving module, and the signal entering the interface passes through the circulator and reaches the downlink receiving module, where the uplink a signal sent by the sending module is sent out from the interface after passing through the circulator;
  • the acquisition module and the analysis module are located on a branch of a line between the circulator and the downlink receiving module; or the acquisition module and the analysis module are located inside the downlink receiving module.
  • the structure of the above CM is mainly applied to the same frequency duplex system.
  • an HFC network fault location system comprising a CM and a direction selective device.
  • the CM has the function of CM behavior in the example of the first aspect above;
  • the direction selective device comprises a branch port, an input port and an output port, the CM being connected to a branch port of the direction selective device;
  • the direction selective device transmits a first uplink signal from the output port downstream of the CM to the CM through the branch port, and isolates from the input port from the CM a second uplink signal downstream, such that the second uplink signal cannot reach the CM; or the direction selective device transmits the second uplink signal to the CM through the branch port, and isolates the a first uplink signal, such that the first uplink signal cannot reach the CM;
  • the direction selecting device selects to transmit the first uplink signal to the CM and isolate the second uplink signal, when the CM detects that the first uplink signal has nonlinear distortion, impulse noise, At least one of intrusion noise and linear distortion under the carrier, the CM determining that at least one of the nonlinear distortion, impulse noise, intrusion noise under the carrier, and linear distortion occurs at the direction selective device Output port side;
  • the direction selecting device selects to transmit the second uplink signal to the CM and isolate the first uplink signal, when the CM detects that the second uplink signal has nonlinear distortion, impulse noise, When at least one of intrusion noise and linear distortion under the carrier, the CM determines that at least one of the nonlinear distortion, impulse noise, intrusion noise under the carrier, and linear distortion occurs in the direction selective device Input port side.
  • the solution provided by the present application provides a direction selective device that can only transmit an uplink signal entering from an output port of the device to a CM connected to a branch port of the device without entering from an input port of the device.
  • the uplink signal is transmitted to the CM of the branch port of the device, so that once the CM detects a fault from the uplink signal, the location of the fault in the HFC network can be accurately located on the output port side of the device; or, the device It is also possible to transmit only the upstream signal from the input port of the device to the CM connected to the branch port of the device, without transmitting the uplink signal from the output port of the device to the CM connected to the branch port of the device, thereby The CM detects a fault from the uplink signal and can accurately locate the faulty location in the HFC network on the input port side of the Tap.
  • the direction selective device is further configured to: from the input port The incoming downlink signal sent by the CMTS to the CM is transmitted to the CM through the branch port; and the third uplink signal sent from the branch port and sent by the CM to the CMTS is passed through the The input port is transmitted to the CMTS.
  • the direction selective device when the direction selective device transmits the first uplink signal to the CM and isolates the second uplink signal, the direction selective device further includes a first branch, a ring , a first duplexer, a second splitter, and a second duplexer;
  • the output port transmits the first uplink signal to the circulator through a branch link of the first brancher; the circulator transmits the first uplink signal to the first duplex in one direction a low pass filter in the first duplexer; the low pass filter in the first duplexer transmits the first uplink signal to the CM through the branch port; the input port sends the second uplink signal Transmitting to the second duplexer through a branch link of the second splitter; the second duplexer transmitting the second uplink signal through a low pass filter in the second duplexer And the circulator, wherein the circulator transmits the second uplink signal to the first brancher, and the first brancher passes the second uplink signal to the first branch The branch link of the device is sent to the output port for issue.
  • the direction selective device when the direction selective device transmits the first uplink signal to the CM, and isolates the second uplink signal, the direction selective device further includes a first brancher, An isolator, a distributor, a second isolator, a first duplexer, a second splitter, and a second duplexer;
  • the output port sends the first uplink signal to the first isolator through a branch link of the first brancher; the first isolator transmits the first uplink signal to the first direction a distributor that transmits the first uplink signal to a low pass filter in the first duplexer; a low pass filter in the first duplexer to the first uplink signal Transmitting to the CM through the branch port;
  • the input port sends the second uplink signal through a branch link of the second branch To the second duplexer; the second duplexer transmits the second uplink signal to the second isolator through a low pass filter in the second duplexer; An isolator blocks the second upstream signal from entering the dispenser.
  • the third aspect of the present application provides a fault detection method, which is used to detect whether there is a fault in the uplink signal arriving at the CM and what fault exists, and the device involved in the method may be the CM in the example of the foregoing first aspect.
  • the specific process refer to the detailed description of the CM in the above first aspect, and details are not described herein again.
  • FIG. 1 is a schematic diagram of a typical HFC network in the prior art
  • FIG. 2 is a schematic structural diagram of an implementation of extending a downlink FBC function of a CM to an uplink in the prior art
  • FIG. 3 is a schematic diagram of an upstream and downstream of a CM according to an embodiment of the present disclosure
  • FIG. 4 is a schematic diagram of a format of a MAP Information Elements in the prior art
  • FIG. 5 is a schematic diagram of a format of a Probe Information Elements in the prior art
  • FIG. 6A is a schematic structural diagram of a first CM according to an embodiment of the present application.
  • 6B is a schematic structural diagram of a second CM according to an embodiment of the present application.
  • 6C is a schematic structural diagram of a third CM according to an embodiment of the present application.
  • 6D is a schematic structural diagram of a fourth CM according to an embodiment of the present application.
  • 7A is a histogram of a time domain sampled value of an uplink signal conforming to a Gaussian distribution according to an embodiment of the present disclosure
  • 7B is a histogram of a time domain sampled value of an uplink signal that does not conform to a Gaussian distribution according to an embodiment of the present disclosure
  • FIG. 8 is a schematic structural diagram of a direction selective device implemented by adjusting isolation according to an embodiment of the present application.
  • FIG. 9A is a schematic diagram of a direction selective device implemented by a circulator according to an embodiment of the present application. Schematic;
  • FIG. 9B is a schematic diagram of a transmission path of a downlink signal entering from an input port in the direction selective device shown in FIG. 9A;
  • FIG. 9C is a schematic diagram of a transmission path of an uplink signal entering from a branch port in the direction selective device shown in FIG. 9A;
  • 9D is a schematic diagram of a transmission path of an uplink signal entering from an output port in the direction selective device shown in FIG. 9A;
  • 9E is a schematic diagram of a transmission path of an uplink signal entering from an input port in the direction selective device shown in FIG. 9A;
  • FIG. 10A is a schematic structural diagram of another direction selective device implemented by a circulator according to an embodiment of the present application.
  • FIG. 10B is a schematic diagram of a transmission path of a downlink signal entering from an input port in the direction selective device shown in FIG. 10A;
  • FIG. 10C is a schematic diagram of a transmission path of an uplink signal entering from a branch port in the direction selective device shown in FIG. 10A;
  • 10D is a schematic diagram of a transmission path of an uplink signal entering from an output port in the direction selective device shown in FIG. 10A;
  • 10E is a schematic diagram of a transmission path of an uplink signal entering from an input port in the direction selective device shown in FIG. 10A;
  • 11A is a schematic structural diagram of a direction selective device implemented by an isolator according to an embodiment of the present application.
  • FIG. 11B is a schematic diagram of a transmission path of a downlink signal entering from an input port in the direction selective device shown in FIG. 11A;
  • FIG. 11C is a schematic diagram of a transmission path of an uplink signal entering from a branch port in the direction selective device shown in FIG. 11A;
  • 11D is a schematic diagram of a transmission path of an uplink signal entering from an output port in the direction selective device shown in FIG. 11A;
  • 11E is a schematic diagram of a transmission path of an uplink signal entering from an input port in the direction selective device shown in FIG. 11A;
  • 12A is a schematic structural diagram of a direction selective device implemented by an isolator according to an embodiment of the present application
  • FIG. 12B is a schematic diagram of a transmission path of a downlink signal entering from an input port in the direction selective device shown in FIG. 12A;
  • FIG. 12C is a schematic diagram of a transmission path of an uplink signal entering from a branch port in the direction selective device shown in FIG. 12A;
  • FIG. 12D is a schematic diagram of a transmission path of an uplink signal entering from an output port in the direction selective device shown in FIG. 12A;
  • FIG. 12E is a schematic diagram of a transmission path of an uplink signal entering from an input port in the direction selective device shown in FIG. 12A;
  • FIG. 13 is a schematic structural diagram of components of a HFC network fault location system according to an embodiment of the present disclosure.
  • FIG. 14 is a flowchart of a fault detection method according to an embodiment of the present application.
  • upstream of a certain CM refers to the side close to the CMTS by the CM; similarly, the “downstream” of a certain CM refers to the side that is bounded by the CM and away from the CMTS.
  • the left side of CM2 is upstream of CM2
  • the right side of CM2 is downstream of CM2, wherein CM1 is located upstream of CM2, and CM3, CM4, and CM5 are located downstream of CM2.
  • upstream is sometimes used to refer to the input port side of the direction selective device provided by the present application
  • downstream is used to refer to the output port side of the direction selective device.
  • the uplink signal refers to the signal sent by the CM to the CMTS.
  • the uplink signal is generally a low frequency signal.
  • the frequency of the uplink signal may be less than 100 megahertz (unit: M).
  • the “downlink signal” refers to the signal sent by the CMTS to the CM, and the downlink signal is generally a high frequency signal. Due to the up signal and the next The frequency band of the line signal is different, so the uplink signal and the downlink signal can be transmitted on the same transmission medium.
  • Nonlinear distortion refers to a new frequency component other than the frequency component of the input signal generated during signal transmission.
  • HFC network it mainly includes gain compression, laser clipping, combined second-order distortion, combined third-order beat, common path distortion, and the like.
  • Pulse noise the noise is characterized by wide frequency and short duration, generally in microseconds (unit: us) or milliseconds (unit: ms), and the intensity is large.
  • Intrusion noise the noise is characterized by a narrow band, long duration or always exists, and the intensity is relatively small.
  • White noise refers to the noise whose power spectral density is evenly distributed throughout the frequency domain. The noise is characterized by an increase in the overall noise floor and a long duration.
  • the "upstream bandwidth allocation mapping message”, which may be simply referred to as "MAP message”, is used to specify which uplink signal is sent by the time interval corresponding to each time slot of each CM. Since the HFC network is a point-to-multipoint network, when each CM transmits an uplink signal, all CMs share an uplink channel. In order to prevent the uplink signals of the respective CMs from colliding, the uplink bandwidth allocation is required, and the uplink channel is divided into different segments from frequency and time, and only one CM is allowed to transmit the uplink signal in one segment.
  • the CMTS periodically allocates the uplink bandwidth according to the request of each CM, and broadcasts the result of the allocation into a MAP message to all CMs. The CM parses the MAP message and selects the time slot that belongs to itself to send the uplink signal.
  • Version 1MAP messages can be analyzed by DOCSIS 1.0, DOCSIS 1.1, DOCSIS 2.0, DOCSIS 3.0, and DOCSIS 3.1 devices and used for time division multiple access (TDMA) and synchronous code division multiple access (Synchronous Code).
  • TDMA time division multiple access
  • S-CDMA synchronous code division multiple access
  • Version 5MAP can only be analyzed by DOCSIS 3.1 devices and used for Orthogonal Frequency Division Multiple Access (Orthogonal Frequency) Division Multiple Access (OFDMA) The bandwidth allocation of the upstream channel.
  • OFDMA Orthogonal Frequency Division Multiple Access
  • the Version 5 MAP for OFDMA uplink channel bandwidth allocation is further divided into two structures according to the allocation content: one is a MAP sub-structure for non-probe frame allocation, and the structure is similar to the Version 1 MAP message; The other is a P-MAP (Probe MAP) substructure for probe frame allocation.
  • the Version 1 MAP message is similar in structure to the Version 5 MAP message for non-probe frame allocation, including an Upstream Channel ID, an MAP Information Element, and other content.
  • the Upstream channel ID identifies which upstream channel the current MAP message is for, and the MAP Information Elements describes the specific usage of each time slot and specifies the time for each CM to send an uplink signal.
  • the structure of MAP Information Elements is shown in Figure 4, and each row in Figure 4 represents the use of a particular time interval.
  • the service flow identifier (SID) identifies which CM or all the CMs are in the current time interval, including the request, multicast, broadcast, and unicast scenarios.
  • the interval usage code (referred to as the IUC) is used to describe the signal type of the SID.
  • Version 5 MAP messages for probe frame allocation include Upstream channel ID, Probe Information Elements (P-IE) and other content.
  • the Upstream channel ID identifies which upstream channel the current MAP message is for, and Probe Information Elements describes the specific usage of each time slot, ie the time and effect of each CM transmitting the Probe signal.
  • the structure of the Probe Information Elements is shown in Fig. 5. Each row in Fig. 5 indicates the usage of each time interval, and the specific case where the CM transmits the Probe signal is expressed. Each CM will match the SID and select its own time slot for the transmission of the Probe signal.
  • a detailed description of each parameter in Figure 5 can be found in the DOCSIS specification "CM-SP-MULPIv3.1".
  • the prior art proposes a The FBC function is extended to the uplink method, but the method of combining the uplink signal into the FBC for acquisition and detection by the switch has the following problems:
  • intrusion noise and white noise outside the carrier can be detected, but other fault problems such as intrusion noise and impulse noise under the carrier cannot be detected.
  • the reason is that the intrusion noise lasts for a long time or always exists.
  • the intrusion noise outside the carrier can be collected at any time through the opening of the switch.
  • the intrusion noise and the service signal are mixed in the same frequency band, it is difficult to separately obtain the intrusion noise under the carrier.
  • the duration of the impulse noise is very short, ranging from 100 ns to 10 ms. For such a short duration, it is difficult to capture the impulse noise through the opening of the switch.
  • the TAP in the HFC network there are multiple ports in the TAP in the HFC network, including the upstream input port, the downstream output port, and the branch port connected to the CM.
  • the signal can run from one port to any other port. Therefore, the CM of a certain port detects noise, and it is impossible to know which port of the Tap is coming in from the port, which may cause noise positioning to be blurred and accurate noise positioning cannot be performed.
  • the opening of the switch in FIG. 2 causes a part of the uplink signal to be mixed into the downlink signal collection and analysis, which may interfere with the resolution of the downlink signal, which may cause service interruption and affect the user experience.
  • this application proposes a CM and HFC network fault location system and fault detection method.
  • the conventional CM is modified to allow the CM to detect not only intrusive noise and white noise outside the carrier, but also nonlinear distortion. Other faults such as impulse noise, intrusive noise under the carrier, and linear distortion, and the CM does not affect the progress of the service while detecting the fault.
  • the present application also provides a direction selective device that can only transmit an upstream signal entering from an output port of the device to a CM connected to a branch port of the device without input from the device.
  • the uplink signal that the port enters is transmitted to the CM connected to the branch port of the device, so that once the CM detects a fault from the uplink signal, the location where the fault occurs in the HFC network can be accurately located on the output port side of the device; or
  • the device may also transmit only the uplink signal entering from the input port of the device to the CM connected to the branch port of the device, without transmitting the uplink signal entering from the output port of the device to the CM connected to the branch port of the device.
  • the CM detects a fault from the uplink signal, it can accurately locate the location of the fault in the HFC network on the input port side of the Tap.
  • CM with the uplink signal acquisition and analysis function provided by the present application is first introduced.
  • the CM can have various structures, and the present application is described by taking only the following four structures as an example.
  • the structure of the first possible CM 60 is shown in FIG. 6A, and includes an interface 601, an uplink sending module 602, a downlink receiving module 603, a duplexer 604, an acquisition module 605, and an analysis module 606.
  • the interface 601, the uplink sending module 602, the downlink receiving module 603, and the duplexer 604 are common modules of the conventional CM.
  • the collection module 605 and the analysis module 606 are new modules of the CM 60 for the present application.
  • the duplexer 604 is connected to the interface 601, and a low pass filter (ie, "L" in FIG. 6A) in the duplexer 604 is connected to the uplink sending module 602, and the duplexer 604
  • the high pass filter 604 i.e., "H” in FIG. 6A
  • the acquisition module 605 and the analysis module 606 are located on a branch of the line between the duplexer 604 and the upstream transmission module 602.
  • the structure of the second possible CM 60 is shown in FIG. 6B, and includes an interface 601, an uplink sending module 602, a downlink receiving module 603, a duplexer 604, an acquisition module 605, and an analysis module 606.
  • the duplexer 604 is connected to the interface 601.
  • the low-pass filter in the duplexer 604 is connected to the uplink sending module 602.
  • the high-pass filter 604 and the high-pass filter 604 in the duplexer 604 The downlink receiving module 603 is connected.
  • the acquisition module 605 and the analysis module 606 are located on a branch of the line between the duplexer 604 and the interface 601.
  • the structure of the third possible CM 60 is shown in FIG. 6C, and includes an interface 601, an uplink sending module 602, a downlink receiving module 603, an acquiring module 605, an analyzing module 606, and a circulator 607.
  • the three ports of the circulator 607 are respectively connected to the interface 601, the uplink sending module 602, and the downlink receiving module 603, and the signal entering from the interface 601 passes through the circulator 607 and arrives at the port.
  • the downlink receiving module 603 sends a signal sent by the uplink sending module 602 from the interface 601 after passing through the circulator 607.
  • the acquisition module 605 and the analysis module 606 can be located on a branch of the line between the circulator 607 and the downstream receiving module 603.
  • the structure of the fourth possible CM 60 is shown in FIG. 6D, and includes an interface 601, an uplink sending module 602, a downlink receiving module 603, an acquiring module 605, an analyzing module 606, and a circulator 607.
  • the three ports of the circulator 607 are respectively associated with the interface 601, the uplink sending module 602, and the lower
  • the line receiving module 603 is connected, and the signal entering from the interface 601 passes through the circulator 607 and then reaches the downlink receiving module 603.
  • the signal sent by the uplink sending module 602 passes through the circulator 607 and then from the interface 601. issue.
  • the collection module 605 and the analysis module 606 may also be located inside the downlink receiving module 603.
  • the structure of the CM shown in FIG. 6A and FIG. 6B is mainly applied to the frequency division system, and the structure of the CM shown in FIG. 6C and FIG. 6D is mainly applied to the same-frequency duplex system.
  • the modules shared by the four structures such as the interface 601, the uplink sending module 602, the downlink receiving module 603, the collecting module 605, and the analyzing module 606, these modules
  • the functions implemented are all similar.
  • the uplink sending module 602 is configured to send an uplink signal to the CMTS by using the interface 601.
  • the downlink receiving module 603 is configured to receive, by using the interface 601, a downlink signal from the CMTS.
  • Upstream and/or downstream upstream signals from the CM 60 enter the CM 60 through the interface 601.
  • the collecting module 605 is configured to collect an uplink signal from the downstream of the CM 60, or collect an uplink signal from an upstream of the CM 60, or collect an upstream signal from the upstream and downstream of the CM 60.
  • the analyzing module 606 is configured to detect whether the uplink signal has at least one of intrusion noise, white noise, nonlinear distortion, impulse noise, intrusion noise under the carrier, and linear distortion.
  • the collection module 605 collects the uplink signal
  • the following three manners may be used.
  • the collecting module 605 determines the time interval corresponding to the empty time slot or the silent detection signal according to the MAP message sent by the CMTS, and collects the time interval corresponding to the empty time slot or the silent detection signal.
  • the upstream signal is described.
  • the MAP message is used to indicate a MAP time slot occupied by each CM under the jurisdiction of the CMTS, and the empty time slot or the silence detection signal indicates that it is not Any MAP slot occupied by the CM.
  • the collection module 605 determines the SID of any one of the upstream device of the CM 60 or the downstream device of the CM 60 according to the MAP message sent by the CMTS, and is in any one of the devices.
  • the uplink signal is collected during a time interval corresponding to the SID.
  • the collecting module 605 can also set other conditions, match the set condition with the MAP message, and trigger the collecting of the uplink signal in the time interval corresponding to the qualified time slot.
  • the set condition may be one or more of Upstream channel ID, SID, IUC, and offset.
  • the set condition may be one or more of Upstream channel ID, SID, Equalization (EQ), and Stagger.
  • the collection module 605 randomly collects the uplink signal.
  • the CM immediately triggers the collection module 605 to collect the uplink signal when receiving the command of the network management.
  • the analysis module 606 when the analysis module 606 analyzes the types of faults in the uplink signal, different detection modes may be adopted according to different fault types.
  • the analyzing module 606 may determine, by using a spectrum analysis manner, the uplink signal according to each frequency component and a frequency distribution range in the uplink signal. Whether there is intrusive noise and white noise outside the carrier.
  • the analysis module 606 can draw a histogram according to the time domain sampled value of the uplink signal. If the histogram is drawn to conform to a Gaussian distribution, as shown in FIG. 7A, the analysis module 606 may determine that the uplink signal does not have nonlinear distortion; otherwise, if the drawn histogram does not conform to a Gaussian distribution, The analysis module 606 can determine that there is nonlinear distortion in the uplink signal.
  • the histogram that does not conform to the Gaussian distribution can be expressed as a histogram asymmetry, two peaks appearing in the histogram, and spikes appearing in the histogram. For example, the histogram shown in Fig.
  • the acquisition module 605 may further include a band pass filter, and the uplink signal may pass through the band pass filter before being collected by the acquisition module.
  • the bandpass filter in this case is an analog bandpass filter.
  • the uplink signal may also be collected by the acquisition module, and then input by the acquisition module into the band pass filter, and the band pass filter in this case is a digital filter. The uplink signal is collected again after passing through the band pass filter, and the center frequency of the band pass filter is outside the uplink working frequency band of the CM 60.
  • the analysis module 606 may determine that the uplink signal has impulse noise; if the energy in the passband of the bandpass filter does not reach The set threshold may be determined by the analysis module 606 that the uplink signal does not have impulse noise.
  • the analysis module 606 can also perform statistics on impulse noise. For example, when the energy in the passband of the bandpass filter reaches a set threshold, the analysis module 606 can begin with a pulse event when the energy in the passband drops from the set threshold. The analysis module 606 can record the end of this pulse event when it is below a set threshold. The analysis module 606 can record the start time and end time of each pulse event, the duration of each pulse event, the average energy of each pulse event for the duration, and the pulse event per second for a period of time. The number of times, etc., to monitor the impulse noise.
  • the acquiring module 605 may adopt the first mode of collecting, that is, the time corresponding to the empty time slot or the silent detection signal by the collecting module 605.
  • the uplink signal is acquired within an interval. If the collecting module 605 collects the uplink signal, the analyzing module 606 may further determine, by using spectrum analysis, whether the uplink signal has intrusion noise under the carrier; if the collecting module 605 does not collect the uplink signal The analysis module 606 can determine that the uplink signal does not have intrusion noise under the carrier.
  • the collecting module 605 may adopt the foregoing second collecting mode, that is, the collecting module 605 collects the time interval corresponding to the SID of any one of the devices.
  • the uplink signal at which time the uplink signal collected by the acquisition module 605 is Specifies the upstream signal of the CM.
  • the analysis module 606 analyzes the uplink signal collected by the collection module 605, such as performing spectrum analysis, to determine whether the uplink signal has linear distortion.
  • the analyzing module 606 can also be used to monitor signal quality of the specified device.
  • the analysis module 606 can demodulate the uplink signal to obtain a signal quality parameter of the uplink signal, and the signal quality parameter can include an equalization coefficient, a modulation error ratio (abbreviation: MER), and a level.
  • the analyzing module 606 may further obtain a test signal of the any one of the devices, by comparing the test signal with the uplink signal collected by the collecting module 605, to obtain the CM and the any one of the A line transmission characteristic between the devices; wherein the test signal is an initial state signal when the uplink signal is sent from any one of the devices.
  • the present application also provides a directional selective device that is an improvement over conventional Tap.
  • the upstream signal from the upstream ie, the input port side of the Tap
  • the downstream ie, the output port side of the Tap
  • the direction selective device provided by the present application may only allow an uplink signal in one direction to flow into the branch port of the direction selective device, for example, only from the upstream (ie, the input port side of the direction selective device).
  • the upstream signal flows into the branch port of the direction selective device, or only the upstream signal from the downstream (ie, the output port side of the direction selective device) flows into the branch port of the direction selective device in.
  • the direction selective device can be implemented by adjusting the isolation of the conventional Tap.
  • a possible directional selective device is constructed as shown in FIG. 8, and the directional selective device includes an input port, an output port, and a branch port.
  • the isolation between the output port and the branch port satisfies the following conditions: an uplink signal flowing from the output port to the branch port and an intensity of an uplink signal flowing from the input port to the branch port Ratio, below the set threshold.
  • the isolation between the output port and the branch port is generally only about 30 dB, and the isolation between the input port and the branch port is generally 20 dB, which indicates the uplink signal flowing from the output port to the branch port.
  • 10% of the upstream signal flowing from the input port to the branch port Since this ratio is relatively high, it can be considered that the uplink signal entering from the input port in the conventional Tap and the uplink signal entering from the output port will flow into the branch port.
  • the uplink signal flowing from the output port to the branch port is the uplink flowing from the input port to the branch port. 0.1% of the signal, such that the upstream signal entering from the output port side is negligible, thereby enabling only the upstream signal entering from the output port of the direction selective device to flow into the branch port of the direction selective device.
  • the direction selective device can be implemented by a circulator or an isolator.
  • the circulator generally has three ports, and the signal entering the circulator can only be transmitted in a certain direction. As shown in FIG. 9A, the signal input from the A port of the circulator 905 can only reach the B port, and cannot reach the C port. The signal input by the B port can only reach the C port, and the signal input by the C port can only reach the A port, thereby The ring transmission characteristic of the A port ⁇ B port ⁇ C port ⁇ A port is formed.
  • the isolator is typically two ports, and the signal entering the isolator can only go from one direction to the other. As shown in FIG. 11A, the signal input from the A port of the isolator 1105 can reach the B port, and the signal input from the B port cannot be transmitted to the A port, thereby forming a unidirectional transmission characteristic of the A port ⁇ B port.
  • the directional selective device can have a variety of configurations.
  • the present application only lists four configurations, illustrating how the directional selective device only allows upstream signals from downstream to flow into its branch ports.
  • FIG. 9A a schematic diagram of a directional selective device 90 implemented by a circulator that only allows downstream upstream signals to flow into the branch ports of the device 90.
  • the device 90 includes an input port 901, an output port 902, a branch port 903, a first Tap 904, a circulator 905, a first duplexer 906, a second Tap 907, and a second duplexer 908.
  • the device 90 generally includes an input port 901, an output port 902, and at least one branch port 903.
  • the present application only shows one branch port 903 in FIG. 9A.
  • the device 90 has the following four conditions through mutual cooperation of the above modules:
  • the downlink signal entering from the input port 901 can reach the branch port 903, and the downlink The transmission path of the signal is as shown in Fig. 9B.
  • the input port 901 is configured to send the downlink signal that is entered from the input port 901 to the second duplexer 908 through a branch link of the second Tap 907.
  • the second duplexer 908 is configured to send the downlink signal to a high pass filter in the first duplexer 906 through a high pass filter in the second duplexer 908.
  • a high pass filter in the first duplexer 906 is configured to send the downlink signal to the branch port 903.
  • the uplink signal entering from the branch port 903 can reach the input port 901, and the transmission path of the uplink signal is as shown in FIG. 9C.
  • the branch port 903 is configured to send an uplink signal that is entered from the branch port 903 to the first duplexer 906.
  • the first duplexer 906 is configured to send the uplink signal to the circulator 905 through a low pass filter in the first duplexer 906.
  • the circulator 905 is configured to unidirectionally transmit the uplink signal to a low pass filter in the second duplexer 908.
  • a low pass filter in the second duplexer 908 is configured to send the uplink signal to the input port 901 through a branch link of the second Tap 907.
  • the uplink signal entering from the output port 902 can reach the branch port 903, and the transmission path of the uplink signal is as shown in FIG. 9D.
  • the output port 902 is configured to send the uplink signal to the circulator 905 through a branch link of the first Tap 904.
  • the circulator 905 is configured to unidirectionally transmit the uplink signal to a low pass filter in the first duplexer 906.
  • a low pass filter in the first duplexer 906 is configured to send the uplink signal to the branch port 903.
  • the input port 901 is configured to send the uplink signal to the second duplexer 908 by using a branch link of the second Tap 907.
  • the second duplexer 908 is configured to send the uplink signal to the circulator 905 through a low pass filter in the second duplexer 908.
  • the circulator 905 is configured to unidirectionally transmit the uplink signal to the first Tap 906, where the uplink signal is sent by the first Tap 906 to the branch link of the first Tap 906.
  • the output port 902 is issued.
  • condition 1 and condition 2 are for ensuring normal operation of the CM service when the branch port of the direction selective device is connected to the CM.
  • Condition 3 and Condition 4 above are for achieving directional selectivity of the directional selective device.
  • the positions of the first Tap 906 and the second Tap 907 are interchangeable, thereby obtaining a structural schematic diagram of another direction selective device 100 implemented by the circulator as shown in FIG. 10A.
  • the device 100 also satisfies the four conditions of the device 90, that is, the downlink signal entering from the input port 901 can reach the branch port 903, and the transmission path of the downlink signal is as shown in FIG. 10B.
  • the uplink signal entering from the branch port 903 can reach the input port 901, and the transmission path of the uplink signal is as shown in FIG. 10C.
  • the uplink signal entering from the output port 902 can reach the branch port 903, and the transmission path of the uplink signal is as shown in FIG. 10D.
  • the uplink signal entering from the input port 901 cannot reach the branch port 903, and the transmission path of the uplink signal is as shown in FIG. 10E.
  • FIG. 11A it is a schematic structural diagram of a direction selective device 110 implemented by an isolator that allows only downstream upstream signals to flow into the branch ports of the device 110.
  • the device 110 includes an input port 1101, an output port 1102, a branch port 1103, a first Tap 1104, a first isolator 1105, a distributor 1106, a second isolator 1107, a first duplexer 1108, a second Tap 1109, and The second duplexer 1110.
  • the distributor is generally three ports, including one master port and two branch ports.
  • the signal entering from the master port of the distributor can reach two branch ports, but the signal entering from a branch port of the distributor can only be transmitted. Cannot transfer to another branch port to the primary port.
  • the distributor 1106 includes a C port, a D port, and an E port, wherein the C port and the E port are branch ports.
  • the D port is the master port.
  • the C port and the D port are interworking.
  • the D port and the E port are also interworking. However, the C port and the E port do not communicate with each other.
  • the device 110 generally includes an input port 1101, an output port 1102, and at least one branch port 1103.
  • the present application only shows one branch port 1103 in FIG. 11A.
  • the device 110 has the following four conditions through mutual cooperation of the above modules:
  • the downlink signal entering from the input port 1101 can reach the branch port 1103, and the transmission path of the downlink signal is as shown in FIG. 11B.
  • the input port 1101 is configured to send a downlink signal that is entered from the input port 1101 to the second duplexer 1110 through a branch link of the second Tap 1109.
  • the second duplexer 1110 is configured to send the downlink signal to a high pass filter in the first duplexer 1108 through a high pass filter in the second duplexer 1110.
  • a high pass filter in the first duplexer 1108 is configured to send the downlink signal to the branch port 1103.
  • the uplink signal entering from the branch port 1103 can reach the input port 1101, and the transmission path of the uplink signal is as shown in FIG. 11C.
  • the branch port 1103 is configured to send an uplink signal that is entered from the branch port 1103 to the first duplexer 1108.
  • the first duplexer 1108 is configured to send the uplink signal to the distributor 1106 through a low pass filter in the first duplexer 1108.
  • the distributor 1106 is configured to transmit the uplink signal to the second isolator 1107.
  • the uplink signal Due to the unidirectional transmission characteristic of the first isolator 1105, the uplink signal is blocked by the first isolator 1105 when it reaches the first isolator 1105 of the C port connection from the D port of the distributor 1106. Therefore, the uplink signal can only reach the second isolator 1107 to which the E port is connected from the D port of the distributor 1106.
  • the second isolator 1107 is configured to unidirectionally transmit the uplink signal to a low pass filter in the second duplexer 1110.
  • the low pass filter in the second duplexer 1110 is configured to send the uplink signal to the input port 1101 through a branch link of the second Tap 1109.
  • the uplink signal entering from the output port 1102 can reach the branch port 1103, and the transmission path of the uplink signal is as shown in FIG. 11D.
  • the output port 1102 is configured to send an uplink signal that is entered from the output port 1102 to the first isolator 1105 through a branch link of the first Tap 1104.
  • the first isolator 1105 is configured to transmit the uplink signal to the distributor 1106 in one direction.
  • the distributor 1106 is configured to transmit the uplink signal to a low pass filter in the first duplexer 1108.
  • a low pass filter in the first duplexer 1108 is configured to send the uplink signal to the branch port 1103.
  • the input port 1101 is configured to send an uplink signal that is entered from the input port 1101 to the second duplexer 1110 through a branch link of the second Tap 1109.
  • the second duplexer 1110 is configured to send the uplink signal to the second isolator 1107 through a low pass filter in the second duplexer 1110.
  • the second isolator 1107 is configured to block the uplink signal from entering the distributor 1106.
  • the positions of the first Tap 1104 and the second Tap 1109 are interchangeable, thereby obtaining a structural schematic diagram of another direction selective device 120 implemented by an isolator as shown in FIG. 12A.
  • the device 120 also satisfies the four conditions of the device 110, that is, the downlink signal entering from the input port 1101 can reach the branch port 1103, and the transmission path of the downlink signal is as shown in FIG. 12B.
  • the uplink signal entering from the branch port 1103 can reach the input port 1101, and the transmission path of the uplink signal is as shown in FIG. 12C.
  • the uplink signal entering from the output port 1102 can reach the branch port 1103, and the transmission path of the uplink signal is as shown in FIG. 12D.
  • the uplink signal entering from the input port 1101 cannot reach the branch port 1103, and the transmission path of the uplink signal is as shown in FIG. 12E.
  • CM with uplink signal acquisition and analysis function and the above direction selectivity
  • the devices may be implemented separately or in combination with other technical means.
  • the HFC network fault detection and positioning system may include at least one of the above-described CMs, and further includes at least one of the above-described direction selective devices.
  • the direction selective device includes a branch port, an input port, and an output port, the CM is connected to a branch port of the direction selective device; an input port of the direction selective device is connected to an upstream of the CM, the direction An output port of the selective device is coupled downstream of the CM.
  • the direction selecting means for transmitting a first uplink signal from the downstream of the CM entering the output port of the direction selective device to the CM through a branch port of the direction selective device, and A second upstream signal from the downstream of the CM entering from the input port of the direction selective device is isolated such that the second upstream signal cannot reach the CM.
  • the direction selecting device is configured to transmit the second uplink signal to the CM through the branch port, and isolate the first uplink signal, so that the first uplink signal cannot reach the CM.
  • the direction selecting device selects to transmit the first uplink signal to the CM and isolate the second uplink signal, when the CM detects that the first uplink signal has an intrusion noise outside the carrier, white
  • the CM may determine intrusion noise, white noise, nonlinear distortion, impulse noise, carrier wave under the carrier when at least one of noise, nonlinear distortion, impulse noise, intrusion noise under the carrier, and linear distortion At least one of intrusion noise and linear distortion occurs on the output port side of the direction selective device.
  • the direction selecting device selects to transmit the second uplink signal to the CM and isolate the first uplink signal, when the CM detects that the second uplink signal has intrusion noise outside the carrier, white
  • the CM is used to determine intrusion noise, white noise, nonlinear distortion, impulse noise, carrier outside the carrier At least one of the underlying intrusion noise and linear distortion occurs on the input port side of the direction selective device.
  • the direction selective device is further configured to: enter from the input port by the CMTS a downlink signal sent to the CM is transmitted to the CM through the branch port; and a third uplink signal sent from the branch port and sent by the CM to the CMTS is transmitted to the CMTS through the input port to The CMTS.
  • a downlink signal sent to the CM is transmitted to the CM through the branch port; and a third uplink signal sent from the branch port and sent by the CM to the CMTS is transmitted to the CMTS through the input port to The CMTS.
  • One possible HFC network fault detection location system may include a plurality of cascaded structures as shown in FIG. The system may integrate the plurality of CMs in the structure shown in FIG. 13 with respect to whether there is a fault and a fault condition, and locate a location where a fault may occur in the HFC network.
  • CMs in FIG. 1 are the CMs with the uplink signal acquisition and analysis function in the present application
  • all the taps in FIG. 1 are the direction selective devices in the present application, and these taps only allow the upstream signals from the downstream to flow into Its branch port, then as long as a CM detects a fault, it can be determined that the fault occurs downstream of the CM; and if a fault occurs upstream of a certain CM, the CM cannot detect the fault.
  • FIG. 1 when only CM1 detects intrusion noise and none of the other CMs detect intrusion noise, it can be determined that the intrusion noise occurs at CM2.
  • CM1 and CM2 when pulsing noise is detected by CM1 and CM2 and no impulse noise is detected by other CMs, it can be determined that the impulse noise occurs in one or more of CM3, CM4 and CM5, and subsequent CM3, CM4 and CM5 pass the intensity. Detection can further determine which CM or CM has generated impulse noise.
  • the present application further provides a fault detection method. As shown in FIG. 14, the method includes the following steps:
  • Step 141 The CM collects an uplink signal from the downstream of the CM, or collects an upstream signal from the upstream of the CM, or collects an upstream signal from the upstream and downstream of the CM.
  • Step 142 The CM detects whether the uplink signal has at least one of nonlinear distortion, impulse noise, intrusion noise under the carrier, and linear distortion.
  • the CM collects an uplink signal from a downstream of the CM, or collects an uplink signal from an upstream of the CM, or collects an uplink signal from the upstream and downstream of the CM.
  • the CM collects an uplink signal from a downstream of the CM, or collects an uplink signal from an upstream of the CM, or collects an uplink signal from the upstream and downstream of the CM.
  • the CM determines the time interval corresponding to the empty time slot or the silence detection signal according to the uplink bandwidth allocation mapping message delivered by the CMTS, and collects the uplink in the time interval corresponding to the empty time slot or the silence detection signal.
  • the uplink bandwidth allocation mapping message message is used to indicate a time slot occupied by each CM under the jurisdiction of the CMTS, and the empty time slot or silence detection signal indicates a time slot not occupied by any CM.
  • the CM determines, according to the uplink bandwidth allocation mapping message sent by the CMTS, the service identifier SID of any one of the upstream device of the CM or the downstream device of the CM, and in any one of the foregoing
  • the uplink signal is collected within a time interval corresponding to the SID of the device.
  • the CM randomly acquires the uplink signal.
  • the CM may draw a histogram according to the time domain sampled value of the uplink signal when detecting whether the uplink signal has nonlinear distortion; if the drawn histogram does not conform to a Gaussian distribution, The CM determines that there is nonlinear distortion in the uplink signal.
  • the CM collects an uplink signal from a downstream of the CM, or collects an uplink signal from an upstream of the CM, or collects an uplink signal from an upstream and a downstream of the CM
  • the CM The uplink signal after passing through the band pass filter may be collected, or the uplink signal may be collected and then input to the band pass filter for processing, the center frequency of the band pass filter The point is outside the upstream working frequency band of the CM.
  • the CM when detecting, by the CM, whether there is impulse noise in the uplink signal, if the energy in the passband of the band pass filter reaches a set threshold, the CM may determine that the uplink signal has impulse noise. .
  • the CM may determine, by using spectrum analysis, Whether the uplink signal has intrusion noise under the carrier.
  • the CM may determine whether the uplink signal has linear distortion.
  • the CM collects the upper time interval corresponding to the SID of any one of the devices.
  • the CM may further demodulate the uplink signal to obtain a signal quality parameter of the uplink signal, the signal quality parameter including an equalization coefficient, a MER and a level; and/or, the CM acquires the a test signal of any one of the devices; comparing the test signal and the uplink signal, obtaining a line transmission characteristic between the CM and the any one of the devices; the test signal is the uplink signal from the any one of the devices The initial status signal at the time of transmission.
  • the technical solution provided by the present application transforms the conventional CM, so that the CM can not only detect intrusion noise and white noise outside the carrier, but also detect nonlinear distortion, impulse noise, and intrusion noise under the carrier. Other fault problems such as linear distortion, and the CM does not affect the progress of the service while detecting the fault.
  • the present application modifies the conventional Tap so that the Tap has directional selectivity, and can only transmit the uplink signal from the output port of the Tap to the CM connected to the branch port of the Tap, without allowing the Tap from the Tap.
  • the uplink signal entered by the input port is transmitted to the CM connected to the branch port of the Tap, so that once the CM detects the fault from the uplink signal, the location where the fault occurs in the HFC network can be accurately located on the output port side of the Tap; or
  • the Tap can also transmit only the uplink signal from the input port of the Tap to the CM connected to the branch port of the Tap, without transmitting the uplink signal from the output port of the Tap to the CM connected to the branch port of the Tap.
  • the CM detects a fault from the uplink signal, it can accurately locate the location of the fault in the HFC network on the input port side of the Tap.
  • embodiments of the present invention can be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or a combination of software and hardware. Moreover, the invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) including computer usable program code.
  • computer-usable storage media including but not limited to disk storage, CD-ROM, optical storage, etc.
  • the computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device.
  • the apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.
  • These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device.
  • the instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

Abstract

一种CM和HFC网络故障定位系统及故障检测方法，该CM不仅可以检测载波外的侵入噪声和白噪声，还可以检测非线性失真、脉冲噪声、载波下的侵入噪声和线性失真等其它故障问题。该系统包括一种方向选择性装置，该装置可以只让从该装置的输出端口进入的上行信号传输到该装置的分支端口连接的CM，而不让从该装置的输入端口进入的上行信号传输到该装置的分支端口连接的CM，从而一旦该CM从上行信号中检测到故障，能够准确地定位出HFC网络中发生故障的位置在该装置的输出端口侧。

Description

一种CM和HFC网络故障定位系统及故障检测方法 技术领域
本发明涉及通信技术领域，尤其涉及一种电缆调制解调器(Cable Modem，简称：CM)和混合光纤同轴电缆(Hybrid Fiber-Coaxial，简称：HFC)网络故障定位系统及故障检测方法。
背景技术
HFC网络技术是一种经济实用的综合数字服务宽带网接入技术。HFC通常由光纤干线、同轴电缆支线和用户配线网络三部分组成，从有线电视台出来的节目信号先变成光信号在干线上传输；到用户区域后再由光信号转换成电信号，经分配器分配后最后通过同轴电缆送到用户。图1为一种典型的HFC网络，如图1所示，HFC网络可以包括以下设备和器件：网络管理系统、城域网、同轴电缆局端接入设备(Cable Modem Terminal System，简称：CMTS)、光站、CM、用户侧的机顶盒(Set Top Box，简称：STB)、个人电脑(Personal Computer，简称：PC)和光缆(fiber)、同轴电缆(cable)、放大器、分支器(Tap)等，图1中未将各个器件一一示出。
HFC网络长期暴露在外会存在很多故障问题，现有的有线电缆数据服务接口规范(Data Over Cable Service Interface Specifications，DOCSIS)3.1标准针对这些问题设计了强大的主动式网络维护(Proactive Network Maintenance，简称：PNM)故障诊断功能，可通过CM和CMTS对线路进行检测，由CMTS对检测结果进行测试和分析。但CMTS只能检测到上行信号的质量变差，无法得知上行信号变差的突变点。如果可以在上行信道的沿途测量上行信号，就可以分析出上行信号变差的突变点，从而找到故障位置。考虑到HFC网络中存在众多的CM，可以在CM处实现对上行信号的检测。
为了实现在CM处对上行信号进行检测，现有技术提出了一种将CM的下行全频谱扫描(Full Band Capture，简称：FBC)功能扩展到上行的方法，该 方法的简化实现结构如图2所示，其在双工器的前面(即图2中的“1”点)引出一个分支，该分支的另一端连接到下行的FBC模块的前面(即图2中的“2”点)，当该分支的开关闭合时，FBC模块中的模/数转换器(Analog-to-Digital Converter，简称：ADC)便可以采集到上行噪声，从而进行上行噪声分析。这样便使得CM具备了上行噪声采集和上行噪声检测的功能。
但这种利用下行FBC功能检测上行信号的CM一般只能检测上行信号中是否出现载波外的侵入噪声和白噪声这两种有限的噪声类型，无法检测其他的故障问题。
发明内容
本发明实施例提供一种CM和HFC网络故障定位系统及故障检测方法，用以解决现有的CM只能检测载波外的侵入噪声和白噪声这两种有限的噪声类型的问题。
本申请第一方面，提供了一种CM，所述CM包括采集模块和分析模块：
所述采集模块采集来自所述CM的下游的上行信号，或采集来自所述CM的上游的上行信号，或采集来自所述CM的上游和下游混合的上行信号；
所述分析模块检测所述上行信号是否存在侵入噪声、白噪声、非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种。
本申请提供的方案对常规的CM进行改造，让CM不仅可以检测载波外的侵入噪声和白噪声，还可以检测非线性失真、脉冲噪声、载波下的侵入噪声和线性失真等其它故障问题。
在一个可能的设计中，所述采集模块在采集所述上行信号时，可以有以下三种采集方式：
第一种，根据CMTS下发的上行带宽分配映射消息，确定空时隙或静默探测信号对应的时间间隔，并在所述空时隙或静默探测信号对应的时间间隔内采集所述上行信号，所述上行带宽分配映射消息消息用于指示所述CMTS管辖下的各个CM分别占用的时隙，所述空时隙或静默探测信号表示不被任 何CM占用的时隙；
第二种，根据所述CMTS下发的上行带宽分配映射消息消息，确定所述CM的上游设备或所述CM的下游设备中的任一个设备的业务标识SID，并在所述任一个设备的SID对应的时间间隔内采集所述上行信号；
第三种，随机采集所述上行信号。
在一个可能的设计中，所述分析模块在检测所述上行信号是否存在非线性失真时，具体包括：
根据所述上行信号的时域采样值绘制直方图；
若绘制的所述直方图不符合高斯分布，则确定所述上行信号存在非线性失真。
在一个可能的设计中，所述采集模块还包括带通滤波器，所述采集模块采集通过所述带通滤波器后的所述上行信号；或，所述采集模块采集所述上行信号后将采集的所述上行信号输入所述带通滤波器进行处理；所述带通滤波器的中心频点在所述CM的上行工作频段之外；
所述分析模块在检测所述上行信号是否存在脉冲噪声时，具体包括：
若所述带通滤波器的通带内的能量达到设定的阈值，则确定所述上行信号存在脉冲噪声。
在一个可能的设计中，所述采集模块在所述空时隙或静默探测信号对应的时间间隔内采集所述上行信号；
所述分析模块具体用于：
若所述采集模块采集到所述上行信号，则通过频谱分析确定所述上行信号是否存在载波下的侵入噪声。
在一个可能的设计中，所述采集模块在所述任一个设备的SID对应的时间间隔内采集所述上行信号；
所述分析模块具体用于：
确定所述上行信号是否存在线性失真。
在一个可能的设计中，所述分析模块还用于：
解调所述上行信号，得到所述上行信号的信号质量参数，所述信号质量参数包括均衡系数，MER和电平；和/或
获取所述任一个设备的测试信号；对比所述测试信号和所述上行信号，得到所述CM与所述任一个设备之间的线路传输特性；所述测试信号为所述上行信号从所述任一个设备发出时的初始状态信号。
在一个可能的设计中，所述CM还包括接口，上行发送模块，下行接收模块和双工器；
所述双工器与所述接口相连，所述双工器中的低通滤波器与所述上行发送模块相连，所述双工器中的高通滤波器与所述下行接收模块相连；
所述采集模块和所述分析模块位于所述双工器与所述接口之间的线路的分支上；或，所述采集模块和所述分析模块位于所述双工器与所述上行发送模块之间的线路的分支上。
上述这种CM的结构主要应用于频分系统。
在一个可能的设计中，所述CM还包括接口，上行发送模块，下行接收模块和环形器；
所述环形器的三个端口分别与所述接口、所述上行发送模块和所述下行接收模块相连，从所述接口进入的信号经过所述环形器后到达所述下行接收模块，所述上行发送模块发送的信号经过所述环形器后从所述接口发出；
所述采集模块和所述分析模块位于所述环形器与所述下行接收模块之间的线路的分支上；或，所述采集模块和所述分析模块位于所述下行接收模块的内部。
上述这种CM的结构主要应用于同频双工系统。
本申请第二方面，提供了一种HFC网络故障定位系统，所述系统包括CM和方向选择性装置。其中所述CM具有上述第一方面的实例中CM行为的功能；所述方向选择性装置包括分支端口、输入端口和输出端口，所述CM与所述方向选择性装置的分支端口相连；所述方向选择性装置的输入端口连接 所述CM的上游，所述方向选择性装置的输出端口连接所述CM的下游；
所述方向选择性装置将从所述输出端口进入的来自所述CM的下游的第一上行信号通过所述分支端口传输给所述CM，以及隔离从所述输入端口进入的来自所述CM的下游的第二上行信号，使得所述第二上行信号无法到达所述CM；或，所述方向选择性装置将所述第二上行信号通过所述分支端口传输给所述CM，以及隔离所述第一上行信号，使得所述第一上行信号无法到达所述CM；
若所述方向选择性装置选择将所述第一上行信号传输给所述CM以及隔离所述第二上行信号，则当所述CM检测到所述第一上行信号存在非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种时，所述CM确定所述非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种发生在所述方向选择性装置的输出端口侧；
若所述方向选择性装置选择将所述第二上行信号传输给所述CM以及隔离所述第一上行信号，则当所述CM检测到所述第二上行信号存在非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种时，则所述CM确定所述非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种发生在所述方向选择性装置的输入端口侧。
本申请提供的方案提供了一种方向选择性装置，该装置可以只让从该装置的输出端口进入的上行信号传输到该装置的分支端口连接的CM，而不让从该装置的输入端口进入的上行信号传输到该装置的分支端口连接的CM，从而一旦该CM从上行信号中检测到故障，能够准确地定位出HFC网络中发生故障的位置在该装置的输出端口侧；或者，该装置也可以只让从装置的输入端口进入的上行信号传输到该装置的分支端口连接的CM，而不让从该装置的输出端口进入的上行信号传输到该装置的分支端口连接的CM，从而一旦该CM从上行信号张检测到故障，能够准确地定位出HFC网络中发生故障的位置在该Tap的输入端口侧。
在一个可能的设计中，所述方向选择性装置还用于：将从所述输入端口 进入的由CMTS发送给所述CM的下行信号通过所述分支端口传输给所述CM；以及，将从所述分支端口进入的由所述CM发送给所述CMTS的第三上行信号通过所述输入端口传输给所述CMTS。
通过上述实现方式，当方向选择性装置的分支端口与CM相连时，可以保证该CM的业务的正常进行。
在一个可能的设计中，所述方向选择性装置将所述第一上行信号传输给所述CM，以及隔离所述第二上行信号时，所述方向选择性装置还包括第一分支器、环形器、第一双工器、第二分支器和第二双工器；
所述输出端口将所述第一上行信号通过所述第一分支器的分支链路发送至所述环形器；所述环形器将所述第一上行信号单向传输至所述第一双工器中的低通滤波器；所述第一双工器中的低通滤波器将所述第一上行信号通过所述分支端口传输给所述CM；所述输入端口将所述第二上行信号通过所述第二分支器的分支链路发送至所述第二双工器；所述第二双工器将所述第二上行信号通过所述第二双工器中的低通滤波器发送至所述环形器；然后，所述环形器将所述第二上行信号单向传输至所述第一分支器，由所述第一分支器将所述第二上行信号通过所述第一分支器的分支链路发送至所述输出端口发出。
在一个可能的设计中，所述方向选择性装置将所述第一上行信号传输给所述CM，以及隔离所述第二上行信号时，所述方向选择性装置还包括第一分支器、第一隔离器、分配器、第二隔离器、第一双工器、第二分支器和第二双工器；
所述输出端口将所述第一上行信号通过所述第一分支器的分支链路发送至所述第一隔离器；所述第一隔离器将所述第一上行信号单向传输至所述分配器；所述分配器将所述第一上行信号传输至所述第一双工器中的低通滤波器；所述第一双工器中的低通滤波器将所述第一上行信号通过所述分支端口传输给所述CM；
所述输入端口将所述第二上行信号通过所述第二分支器的分支链路发送 至所述第二双工器；所述第二双工器将所述第二上行信号通过所述第二双工器中的低通滤波器发送至所述第二隔离器；所述第二隔离器阻止所述第二上行信号进入所述分配器。
本申请第三方面，提供了一种故障检测方法，该方法用于检测到达CM的上行信号中是否存在故障以及存在何种故障，该方法涉及的设备可以为上述第一方面的实例中的CM，具体流程参见上述第一方面中对CM的详细描述，此处不再赘述。
附图说明
图1为现有技术下一种典型的HFC网络的示意图；
图2为现有技术下一种将CM的下行FBC功能扩展到上行的实现结构示意图；
图3为本申请实施例提供的一种CM的上游和下游的说明示意图；
图4为现有技术下一种MAP Information Elements的格式示意图；
图5为现有技术下一种Probe Information Elements的格式示意图；
图6A为本申请实施例提供的第一种CM的结构示意图；
图6B为本申请实施例提供的第二种CM的结构示意图；
图6C为本申请实施例提供的第三种CM的结构示意图；
图6D为本申请实施例提供的第四种CM的结构示意图；
图7A为本申请实施例提供的一种符合高斯分布的上行信号时域采样值的直方图；
图7B为本申请实施例提供的一种不符合高斯分布的上行信号时域采样值的直方图；
图8为是本申请实施例提供的一种通过调整隔离度实现的方向选择性装置的结构示意图；
图9A为本申请实施例提供的一种通过环形器实现的方向选择性装置的 结构示意图；
图9B为图9A所示的方向选择性装置中从输入端口进入的下行信号的传输路径的示意图；
图9C为图9A所示的方向选择性装置中从分支端口进入的上行信号的传输路径的示意图；
图9D为图9A所示的方向选择性装置中从输出端口进入的上行信号的传输路径的示意图；
图9E为图9A所示的方向选择性装置中从输入端口进入的上行信号的传输路径的示意图；
图10A为本申请实施例提供的另一种通过环形器实现的方向选择性装置的结构示意图；
图10B为图10A所示的方向选择性装置中从输入端口进入的下行信号的传输路径的示意图；
图10C为图10A所示的方向选择性装置中从分支端口进入的上行信号的传输路径的示意图；
图10D为图10A所示的方向选择性装置中从输出端口进入的上行信号的传输路径的示意图；
图10E为图10A所示的方向选择性装置中从输入端口进入的上行信号的传输路径的示意图；
图11A为本申请实施例提供的一种通过隔离器实现的方向选择性装置的结构示意图；
图11B为图11A所示的方向选择性装置中从输入端口进入的下行信号的传输路径的示意图；
图11C为图11A所示的方向选择性装置中从分支端口进入的上行信号的传输路径的示意图；
图11D为图11A所示的方向选择性装置中从输出端口进入的上行信号的传输路径的示意图；
图11E为图11A所示的方向选择性装置中从输入端口进入的上行信号的传输路径的示意图；
图12A为本申请实施例提供的一种通过隔离器实现的方向选择性装置的结构示意图；
图12B为图12A所示的方向选择性装置中从输入端口进入的下行信号的传输路径的示意图；
图12C为图12A所示的方向选择性装置中从分支端口进入的上行信号的传输路径的示意图；
图12D为图12A所示的方向选择性装置中从输出端口进入的上行信号的传输路径的示意图；
图12E为图12A所示的方向选择性装置中从输入端口进入的上行信号的传输路径的示意图；
图13为本申请实施例提供的一种HFC网络故障定位系统的组成部分的结构示意图；
图14为本申请实施例提供的一种故障检测方法的流程图。
具体实施方式
以下，对本申请中的部分用语进行解释说明。
本申请中，某个CM的“上游”是指以该CM为界、靠近CMTS的一侧；同理，某个CM的“下游“是指以该CM为界、远离CMTS的一侧。例如，图3中，CM2的左侧为CM2的上游，CM2的右侧为CM2的下游，其中，CM1位于CM2的上游，CM3、CM4和CM5位于CM2的下游。
本申请中，有时还会使用到“上游”来指代本申请提供的方向选择性装置的输入端口侧，使用到“下游”来指代所述方向选择性装置的输出端口侧。
“上行信号”，是指CM发送给CMTS的信号，上行信号一般为低频信号，例如上行信号的频率可以在100兆(单位：M)以下。相应的，“下行信号”是指CMTS发送给CM的信号，下行信号一般为高频信号。由于上行信号和下 行信号的频段不一样，因此上行信号和下行信号可以在同一根传输介质上传输。
“非线性失真”，是指信号传输过程中产生了输入信号的频率分量以外的新频率分量。在HFC网络中主要包括增益压缩、激光削波、组合二阶失真、组合三阶差拍、公共路径失真等。
“脉冲噪声”，噪声特点为宽频，持续时间短，一般为微秒(单位：us)或毫秒(单位：ms)级，强度大。
“侵入噪声”，噪声特点为窄带，持续时间长或一直存在，强度相对较小。
“白噪声”，是指功率谱密度在整个频域内均匀分布的噪声，噪声特点为会造成总体底噪的抬升，持续时间长。
“线性失真“，输出信号中不会有输入信号中所没有的新的频率分量，各个频率的输出波形也不会变化。
“上行带宽分配映射消息”，可简称为“MAP消息”，用于规定各个CM分别在哪个时隙对应的时间间隔发送何种上行信号。由于HFC网络是点到多点的网络，各个CM在发送上行信号时，所有的CM共用上行信道。为了防止各个CM的上行信号发生冲突，所以需要进行上行带宽分配，将上行信道从频率和时间上分成不同的片段，一个片段只允许一个CM发送上行信号。在具体实现上，一般是CMTS周期性地根据各个CM的请求分配上行带宽，将分配的结果形成MAP消息下行广播给所有的CM，CM解析MAP消息，选择属于自己的时隙发送上行信号。
目前主要有两种MAP消息，分别是版本(Version)1MAP消息和Version 5MAP消息。Version 1MAP消息可以被DOCSIS 1.0、DOCSIS 1.1、DOCSIS 2.0、DOCSIS 3.0和DOCSIS 3.1的设备分析并用于时分多址接入(time division multiple access，简称：TDMA)和同步码分多址接入(Synchronous Code Division Multiple Access，简称：S-CDMA)上行信道的带宽分配。Version 5MAP只能被DOCSIS 3.1的设备分析并用于正交频分多址接入(Orthogonal Frequency  Division Multiple Access，简称：OFDMA)上行信道的带宽分配。而用于OFDMA上行信道带宽分配的Version 5MAP根据分配内容又分为两种结构：一种是用于非探测帧(non-probe frame)分配的MAP子结构，这种结构跟Version 1MAP消息类似；另一种是用于探测帧(probe frame)分配的P-MAP(Probe MAP)子结构。
其中，Version 1MAP消息和用于non-probe frame分配的Version 5MAP消息的结构类似，包括上行信道标识(Upstream channel ID)、MAP信息单元(Information Elements)及其它内容。Upstream channel ID标识了当前MAP消息是针对哪个上行通道，而MAP Information Elements描述了各个时隙的具体使用情况，及规定了各个CM发送上行信号的时间。MAP Information Elements的结构如图4所示，图4中的每一行表示特定的时间间隔的使用情况。其中，业务流标识(简称：SID)标识了当前时间间隔归哪个或哪些CM所有，包括请求、组播、广播、单播等场景；间隔使用码(简称；IUC)用于表述SID的信号类型，当前包括IUC1～IUC15共15种；偏移量(Offset)用于表述当前时间间隔的微时隙偏移量，即时间长度。各个CM会匹配SID，选择属于自己的时隙进行上行信号的发送。图4中各参数的详细介绍可以参见DOCSIS规范《CM-SP-MULPIv3.1》。
用于probe frame分配的Version 5MAP消息包括Upstream channel ID、探测信息单元(Probe Information Elements，简称：P-IE)及其它内容。Upstream channel ID标识了当前MAP消息是针对哪个上行通道，而Probe Information Elements描述了各个时隙的具体使用情况，即各个CM发送Probe信号的时间和作用。Probe Information Elements的结构如图5所示，图5中的每一行表示各个时间间隔的使用情况，表述了CM发送Probe信号的具体情况。各个CM会匹配SID，选择属于自己的时隙进行Probe信号的发送。图5中各参数的详细介绍可参考DOCSIS规范《CM-SP-MULPIv3.1》。
下面结合说明书附图和各实施例对本申请技术方案进行说明。
为了实现在CM处对上行信号进行检测，现有技术提出了一种将CM的下 行FBC功能扩展到上行的方法，但这种通过开关将上行信号合并到FBC中进行采集并进行检测的方法，存在如下的问题：
第一，可以检测载波外的侵入噪声和白噪声，但无法检测载波下的侵入噪声和脉冲噪声等其他故障问题。原因在于，侵入噪声持续时间长或一直存在，通过开关的开启可以随时采集到载波外的侵入噪声，但如果侵入噪声和业务信号混在同一频段上，很难从中分开得到载波下的侵入噪声。而脉冲噪声持续的时间很短，从100ns到10ms不等，如此短的持续时间，通过开关的开启很难捕获脉冲噪声的。
第二，HFC网络中的TAP存在多个端口，包括连接上游的输入端口、连接下游的输出端口和连接CM的分支端口，信号可以从一个端口跑到其它任何一个端口。所以某个端口的CM检测到有噪声，无法知道该噪声是从Tap的哪个端口进来的，从而会导致噪声定位模糊，无法进行准确的噪声定位。
第三，图2中的开关的开启，使得部分上行信号混入到下行信号的采集分析中，会干扰下行信号的解析，有可能导致业务的中断，影响用户体验。
为此，本申请提出了一种CM和HFC网络故障定位系统及故障检测方法，一方面对常规的CM进行改造，让CM不仅可以检测载波外的侵入噪声和白噪声，还可以检测非线性失真、脉冲噪声、载波下的侵入噪声和线性失真等其它故障问题，并且CM在检测故障的同时不会影响业务的进行。另一方面，本申请还提供了一种方向选择性装置，该装置可以只让从该装置的输出端口进入的上行信号传输到该装置的分支端口连接的CM，而不让从该装置的输入端口进入的上行信号传输到该装置的分支端口连接的CM，从而一旦该CM从上行信号中检测到故障，能够准确地定位出HFC网络中发生故障的位置在该装置的输出端口侧；或者，该装置也可以只让从装置的输入端口进入的上行信号传输到该装置的分支端口连接的CM，而不让从该装置的输出端口进入的上行信号传输到该装置的分支端口连接的CM，从而一旦该CM从上行信号张检测到故障，能够准确地定位出HFC网络中发生故障的位置在该Tap的输入端口侧。
下面，首先对本申请提供的具备上行信号采集分析功能的CM进行介绍。所述CM可以有多种结构，本申请仅以下述4种结构为例进行说明。
第一种可能的CM 60的结构参见图6A所示，包括接口601、上行发送模块602、下行接收模块603、双工器604、采集模块605和分析模块606。其中，所述接口601、上行发送模块602、下行接收模块603和双工器604为目前常规的CM具备的通用模块。所述采集模块605和分析模块606为本申请为CM 60新增的模块。所述双工器604与所述接口601相连，所述双工器604中的低通滤波器(即图6A中的“L”)与所述上行发送模块602相连，所述双工器604中的高通滤波器604(即图6A中的“H”)与所述下行接收模块603相连。所述采集模块605和所述分析模块606位于所述双工器604与所述上行发送模块602之间的线路的分支上。
第二种可能的CM 60的结构参见图6B所示，包括接口601、上行发送模块602、下行接收模块603、双工器604、采集模块605和分析模块606。其中，所述双工器604与所述接口601相连，所述双工器604中的低通滤波器与所述上行发送模块602相连，所述双工器604中的高通滤波器604与所述下行接收模块603相连。所述采集模块605和所述分析模块606位于所述双工器604与所述接口601之间的线路的分支上。
第三种可能的CM 60的结构参见图6C所示，包括接口601、上行发送模块602、下行接收模块603、采集模块605、分析模块606和环形器607。其中，所述环形器607的三个端口分别与所述接口601、所述上行发送模块602和所述下行接收模块603相连，从所述接口601进入的信号经过所述环形器607后到达所述下行接收模块603，所述上行发送模块602发送的信号经过所述环形器607后从所述接口601发出。所述采集模块605和所述分析模块606可以位于所述环形器607与所述下行接收模块603之间的线路的分支上。
第四种可能的CM 60的结构参见图6D所示，包括接口601、上行发送模块602、下行接收模块603、采集模块605、分析模块606和环形器607。其中，所述环形器607的三个端口分别与所述接口601、所述上行发送模块602和所述下 行接收模块603相连，从所述接口601进入的信号经过所述环形器607后到达所述下行接收模块603，所述上行发送模块602发送的信号经过所述环形器607后从所述接口601发出。所述采集模块605和所述分析模块606也可以位于所述下行接收模块603的内部。
其中，图6A和图6B所示的CM的结构主要应用于频分系统，图6C和图6D所示的CM的结构主要应用于同频双工系统。
无论CM 60采取何种结构，这4种结构共有的模块，如所述接口601、所述上行发送模块602、所述下行接收模块603、所述采集模块605和所述分析模块606，这些模块所实现的功能都是类似的。
具体的，所述上行发送模块602，用于通过所述接口601向CMTS发送上行信号。
所述下行接收模块603，用于通过所述接口601接收来自CMTS的下行信号。
来自所述CM 60的下游和/或下游的上行信号通过所述接口601进入所述CM 60。
所述采集模块605，用于采集来自所述CM 60的下游的上行信号，或采集来自所述CM 60的上游的上行信号，或采集来自所述CM 60的上游和下游混合的上行信号。
所述分析模块606，用于检测所述上行信号是否存在载波外的侵入噪声、白噪声、非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种。
本申请中，所述采集模块605在采集所述上行信号时，可以有以下三种方式。
第一种采集方式，所述采集模块605根据CMTS下发的MAP消息，确定空时隙或静默探测信号对应的时间间隔，并在所述空时隙或静默探测信号对应的时间间隔内采集所述上行信号。其中，所述MAP消息用于指示所述CMTS管辖下的各个CM分别占用的MAP时隙，所述空时隙或静默探测信号表示不被 任何CM占用的MAP时隙。
第二种采集方式，所述采集模块605根据CMTS下发的MAP消息，确定所述CM 60的上游设备或所述CM 60的下游设备中的任一个设备的SID，并在所述任一个设备的SID对应的时间间隔内采集所述上行信号。
可选的，所述采集模块605还可以设定其它的条件，将设定的条件与MAP消息进行匹配，在符合条件的时隙所对应的时间间隔内触发采集上行信号。其中，当MAP消息的版本为Version 1或用于non-probe frame分配的Version 5时，设定的条件可以是Upstream channel ID、SID、IUC和offset中的一个或多个。当MAP消息的版本为用于probe frame分配的Version 5时，设定的条件可以是Upstream channel ID、SID、均衡(EQ)和交错(stagger)中的一个或多个。
第三种采集方式，所述采集模块605随机采集所述上行信号。例如，CM在接收到网管的命令时立即触发所述采集模块605采集所述上行信号。
本申请中，所述分析模块606在分析上行信号中存在何种故障类型时，可以根据不同的故障类型采用不同的检测方式。
例如，在检测所述上行信号是否存在载波外的侵入噪声或白噪声时，所述分析模块606可以采用频谱分析的方式，根据上行信号中的各个频率成分和频率分布范围，判断所述上行信号是否存在载波外的侵入噪声和白噪声。
例如，在检测所述上行信号是否存在非线性失真时，所述分析模块606可以根据所述上行信号的时域采样值绘制直方图。若绘制的所述直方图符合高斯分布，如图7A所示，则所述分析模块606可以确定所述上行信号不存在非线性失真；反之，若绘制的所述直方图不符合高斯分布，则所述分析模块606可以确定所述上行信号存在非线性失真。其中，不符合高斯分布的直方图，具体可表现为直方图不对称、直方图出现了两个峰、直方图中出现了尖刺等现象。例如，图7B所示的直方图在尾部出现了尖刺，这样，该直方图便不符合高斯分布，而通过尖刺的分布情况可以知道非线性效应的严重性，尖刺越多、越明显，则表示上行信号的非线性效应越严重。图7A和图7B中的横坐标表示 时域采样值的大小，纵坐标表示对应横坐标的采样值大小出现的次数或概率。
例如，在检测所述上行信号是否存在脉冲噪声时，所述采集模块605还可以包括带通滤波器，所述上行信号可以先通过所述带通滤波器，再被所述采集模块采集，这种情况下的带通滤波器为模拟带通滤波器。或者，所述上行信号也可以先被所述采集模块采集，再被所述采集模块输入所述带通滤波器进行处理，这种情况下的带通滤波器为数字滤波器。所述上行信号通过所述带通滤波器后被再次采集，所述带通滤波器的中心频点在所述CM 60的上行工作频段之外。若所述带通滤波器的通带内的能量达到设定的阈值，则所述分析模块606可以确定所述上行信号存在脉冲噪声；若所述带通滤波器的通带内的能量未达到所述设定的阈值，则所述分析模块606可以确定所述上行信号不存在脉冲噪声。
所述分析模块606还可以进行脉冲噪声的统计。例如，当所述带通滤波器的通带内的能量达到设定的阈值时，所述分析模块606可以记一个脉冲事件开始，当所述通带内的能量从所述设定的阈值下降到低于另一个设定的阈值时，所述分析模块606可以记这个脉冲事件结束。所述分析模块606可以分别记录每个脉冲事件的开始时间和结束时间，每个脉冲事件的持续时间，每个脉冲事件在持续时间内的平均能量，以及一段时间内每秒钟脉冲事件发生的次数等，从而进行脉冲噪声的监测。
例如，在检测所述上行信号是否存在载波下的侵入噪声时，所述采集模块605可以采用上述第一种采集方式，即所述采集模块605在所述空时隙或静默探测信号对应的时间间隔内采集所述上行信号。若所述采集模块605采集到所述上行信号，则所述分析模块606可以通过频谱分析进一步确定所述上行信号是否存在载波下的侵入噪声；若所述采集模块605未采集到所述上行信号，则所述分析模块606可以确定所述上行信号不存在载波下的侵入噪声。
例如，在检测所述上行信号是否存在线性失真时，所述采集模块605可以采用上述第二种采集方式，即所述采集模块605在所述任一个设备的SID对应的时间间隔内采集所述上行信号，此时所述采集模块605采集到的上行信号为 指定CM的上行信号。所述分析模块606通过对所述采集模块605采集到的上行信号进行分析，如进行频谱分析，从而确定所述上行信号是否存在线性失真。
可选的，当所述采集模块605采用上述第二种采集方式时，所述分析模块606还可以用于监测指定设备的信号质量。例如，所述分析模块606可以解调所述上行信号，得到所述上行信号的信号质量参数，所述信号质量参数可以包括均衡系数，调制误差比(简称：MER)和电平等参数。和/或，所述分析模块606还可以获取所述任一个设备的测试信号，通过对比所述测试信号和所述采集模块605采集到的所述上行信号，得到所述CM与所述任一个设备之间的线路传输特性；其中，所述测试信号为所述上行信号从所述任一个设备发出时的初始状态信号。
本申请还提供了一种方向选择性装置，所述方向选择性装置为对常规Tap的改进。常规的Tap中，来自上游(即Tap的输入端口侧)的上行信号以及来自下游(即Tap的输出端口侧)都会流入到分支端口中。而本申请提供的所述方向选择性装置可以只让一个方向的上行信号流入到所述方向选择性装置的分支端口中，例如，只让来自上游(即所述方向选择性装置的输入端口侧)的上行信号流入到所述方向选择性装置的分支端口中，或，只让来自下游(即所述方向选择性装置的输出端口侧)的上行信号流入到所述方向选择性装置的分支端口中。
其中，若要实现只让来自上游的上行信号流入到所述方向选择性装置的分支端口，所述方向选择性装置可以通过调整常规Tap的隔离度来实现。一种可能的方向选择性装置的结构如图8所示，所述方向选择性装置包括输入端口、输出端口和分支端口。所述输出端口和所述分支端口之间的隔离度满足以下条件：从所述输出端口流入到所述分支端口的上行信号与从所述输入端口流入到所述分支端口的上行信号的强度之比，低于设定的阈值。
例如，常规的Tap中，输出端口与分支端口之间的隔离度一般只有30dB左右，而输入端口与分支端口之间的隔离度一般有20dB，这说明从输出端口流入到分支端口的上行信号，为从输入端口流入到分支端口的上行信号的10％， 由于这个比例值比较高，所以可以认为常规的Tap中从输入端口进入的上行信号以及从输出端口进入的上行信号都会流入到分支端口中。而本申请通过将常规的Tap中的输出端口与分支端口之间的隔离度调高，例如调整到50dB，那么从输出端口流入到分支端口的上行信号，为从输入端口流入到分支端口的上行信号的0.1％，如此从输出端口侧进入的上行信号可以忽略不计，从而实现了只让从所述方向选择性装置的输出端口进入的上行信号流入到所述方向选择性装置的分支端口中。
另一方面，若要实现只让来自下游的上行信号流入到所述方向选择性装置的分支端口，所述方向选择性装置可以通过环形器或隔离器来实现。
环形器一般有三个端口，进入环形器的信号只能按照一定的方向进行传输。如图9A中，从环形器905的A端口输入的信号只能到达B端口，而无法到达C端口，B端口输入的信号只能到达C端口，C端口输入的信号只能到达A端口，从而形成A端口→B端口→C端口→A端口的环形传输特性。
隔离器一般为两个端口，进入隔离器的信号只能从一个方向进入另一个方向。如图11A中，从隔离器1105的A端口输入的信号可到达B端口，而从B端口输入的信号无法传输到A端口，从而形成A端口→B端口的单向传输特性。
所述方向选择性装置可以有多种结构，本申请仅列举4种结构，说明所述方向选择性装置如何只让来自下游的上行信号流入到其分支端口。
如图9A所示，为一种通过环形器实现的方向选择性装置90的结构示意图，所述装置90只让下游的上行信号流入到所述装置90的分支端口中。
所述装置90包括输入端口901，输出端口902，分支端口903，第一Tap 904、环形器905、第一双工器906、第二Tap 907和第二双工器908。
需要说明的是，所述装置90一般包括一个输入端口901、一个输出端口902和至少一个分支端口903。为了简洁，本申请在图9A中仅画出了一个分支端口903。
所述装置90通过上述各个模块的相互协作，具备如下四个条件：
条件一，从输入端口901进入的下行信号可以到达分支端口903，该下行 信号的传输路径如图9B所示。
具体的，所述输入端口901，用于将从所述输入端口901进入的所述下行信号通过所述第二Tap 907的分支链路发送至所述第二双工器908。
所述第二双工器908，用于将所述下行信号通过所述第二双工器908中的高通滤波器发送至所述第一双工器906中的高通滤波器。
所述第一双工器906中的高通滤波器，用于将所述下行信号发送至所述分支端口903。
条件二，从分支端口903进入的上行信号可以到达输入端口901，该上行信号的传输路径如图9C所示。
具体的，所述分支端口903，用于将从所述分支端口903进入的上行信号发送至所述第一双工器906。
所述第一双工器906，用于将所述上行信号通过所述第一双工器906中的低通滤波器发送至所述环形器905。
所述环形器905，用于将所述上行信号单向传输至所述第二双工器908中的低通滤波器。
所述第二双工器908中的低通滤波器，用于将所述上行信号通过第二Tap 907的分支链路发送至所述输入端口901。
条件三，从输出端口902进入的上行信号可以到达分支端口903，该上行信号的传输路径如图9D所示。
具体的，所述输出端口902，用于将所述上行信号通过所述第一Tap 904的分支链路发送至所述环形器905。
所述环形器905，用于将所述上行信号单向传输至所述第一双工器906中的低通滤波器。
所述第一双工器906中的低通滤波器，用于将所述上行信号发送至所述分支端口903。
条件四，从输入端口901进入的上行信号无法到达分支端口903，该上行信号的传输路径如图9E所示。
具体的，所述输入端口901，用于将所述上行信号通过所述第二Tap 907的分支链路发送至所述第二双工器908。
所述第二双工器908，用于将所述上行信号通过所述第二双工器908中的低通滤波器发送至所述环形器905。
所述环形器905，用于将所述上行信号单向传输至所述第一Tap 906，由所述第一Tap 906将所述上行信号通过所述第一Tap 906的分支链路发送至所述输出端口902发出。
其中，上述条件一和条件二，是为了当方向选择性装置的分支端口与CM相连时，保证该CM的业务的正常进行。上述条件三和条件四，是为了实现方向选择性装置的方向选择性。
可选的，所述第一Tap 906和所述第二Tap 907的位置可互换，从而得到如图10A所示的另一种通过环形器实现的方向选择性装置100的结构示意图。
所述装置100同样满足上述装置90的四个条件，即从输入端口901进入的下行信号可以到达分支端口903，该下行信号的传输路径如图10B所示。从分支端口903进入的上行信号可以到达输入端口901，该上行信号的传输路径如图10C所示。从输出端口902进入的上行信号可以到达分支端口903，该上行信号的传输路径如图10D所示。从输入端口901进入的上行信号无法到达分支端口903，该上行信号的传输路径如图10E所示。
如图11A所示，为一种通过隔离器实现的方向选择性装置110的结构示意图，所述装置110只让下游的上行信号流入到所述装置110的分支端口中。
所述装置110包括输入端口1101，输出端口1102，分支端口1103，第一Tap 1104、第一隔离器1105、分配器1106、第二隔离器1107、第一双工器1108、第二Tap 1109和第二双工器1110。
分配器一般为三个端口，其中包括一个主端口和两个分支端口，从分配器的主端口进入的信号可以到达两个分支端口，但从分配器的某个分支端口进入的信号只能传输到主端口而无法传输到另一个分支端口。如图11A中，所述分配器1106包括C端口、D端口和E端口，其中，C端口和E端口为分支端口， D端口为主端口，C端口和D端口之间是互通的，D端口和E端口之间也是互通的，但C端口和E端口之间不互通。
需要说明的是，所述装置110一般包括一个输入端口1101、一个输出端口1102和至少一个分支端口1103。为了简洁，本申请在图11A中仅画出了一个分支端口1103。
所述装置110通过上述各个模块的相互协作，具备如下四个条件：
条件一，从输入端口1101进入的下行信号可以到达分支端口1103，该下行信号的传输路径如图11B所示。
具体的，所述输入端口1101，用于将从所述输入端口1101进入的下行信号通过所述第二Tap 1109的分支链路发送至所述第二双工器1110。
所述第二双工器1110，用于将所述下行信号通过所述第二双工器1110中的高通滤波器发送至所述第一双工器1108中的高通滤波器。
所述第一双工器1108中的高通滤波器，用于将所述下行信号发送至所述分支端口1103。
条件二，从分支端口1103进入的上行信号可以到达输入端口1101，该上行信号的传输路径如图11C所示。
具体的，所述分支端口1103，用于将从所述分支端口1103进入的上行信号发送至所述第一双工器1108。
所述第一双工器1108，用于将所述上行信号通过所述第一双工器1108中的低通滤波器发送至所述分配器1106。
所述分配器1106，用于将所述上行信号传输至所述第二隔离器1107。
由于所述第一隔离器1105的单向传输特性，所述上行信号从所述分配器1106的D端口到达C端口连接的第一隔离器1105时会被所述第一隔离器1105所阻止，因此所述上行信号只能从所述分配器1106的D端口到达E端口所连接的第二隔离器1107。
所述第二隔离器1107，用于将所述上行信号单向传输所述第二双工器1110中的低通滤波器。
所述第二双工器1110中的低通滤波器，用于将所述上行信号通过第二Tap 1109的分支链路发送至所述输入端口1101。
条件三，从输出端口1102进入的上行信号可以到达分支端口1103，该上行信号的传输路径如图11D所示。
具体的，所述输出端口1102，用于将从所述输出端口1102进入的上行信号通过所述第一Tap 1104的分支链路发送至所述第一隔离器1105。
所述第一隔离器1105，用于将所述上行信号单向传输至所述分配器1106。
所述分配器1106，用于将所述上行信号传输至所述第一双工器1108中的低通滤波器。
所述第一双工器1108中的低通滤波器，用于将所述上行信号发送至所述分支端口1103。
条件四，从输入端口1101进入的上行信号无法到达分支端口1103，该上行信号的传输路径如图10E所示。
具体的，所述输入端口1101，用于将从所述输入端口1101进入的上行信号通过所述第二Tap 1109的分支链路发送至所述第二双工器1110。
所述第二双工器1110，用于将所述上行信号通过所述第二双工器1110中的低通滤波器发送至所述第二隔离器1107。
所述第二隔离器1107，用于阻止所述上行信号进入所述分配器1106。
可选的，所述第一Tap 1104和所述第二Tap 1109的位置可互换，从而得到如图12A所示的另一种通过隔离器实现的方向选择性装置120的结构示意图。
所述装置120同样满足上述装置110的四个条件，即从输入端口1101进入的下行信号可以到达分支端口1103，该下行信号的传输路径如图12B所示。从分支端口1103进入的上行信号可以到达输入端口1101，该上行信号的传输路径如图12C所示。从输出端口1102进入的上行信号可以到达分支端口1103，该上行信号的传输路径如图12D所示。从输入端口1101进入的上行信号无法到达分支端口1103，该上行信号的传输路径如图12E所示。
需要说明的是，上述具备上行信号采集分析功能的CM和上述方向选择性 装置可以分别单独实施，也可以与其它技术手段配合实施。
若将上述具备上行信号采集分析功能的CM和上述方向选择性装置组合实施，即为本申请提供的一种HFC网络故障检测定位系统的组成部分。
所述HFC网络故障检测定位系统可以包括至少一个上述CM，以及还包括至少一个上述方向选择性装置。
所述方向选择性装置包括分支端口、输入端口和输出端口，所述CM与所述方向选择性装置的分支端口相连；所述方向选择性装置的输入端口连接所述CM的上游，所述方向选择性装置的输出端口连接所述CM的下游。
所述方向选择性装置，用于将从所述方向选择性装置的输出端口进入的来自所述CM的下游的第一上行信号通过所述方向选择性装置的分支端口传输给所述CM，以及隔离从所述方向选择性装置的输入端口进入的来自所述CM的下游的第二上行信号，使得所述第二上行信号无法到达所述CM。或者，所述方向选择性装置用于将所述第二上行信号通过所述分支端口传输给所述CM，以及隔离所述第一上行信号，使得所述第一上行信号无法到达所述CM。
若所述方向选择性装置选择将所述第一上行信号传输给所述CM以及隔离所述第二上行信号，则当所述CM检测到所述第一上行信号存在载波外的侵入噪声、白噪声、非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种时，所述CM可以确定所述载波外的侵入噪声、白噪声、非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种发生在所述方向选择性装置的输出端口侧。
若所述方向选择性装置选择将所述第二上行信号传输给所述CM以及隔离所述第一上行信号，则当所述CM检测到所述第二上行信号存在载波外的侵入噪声、白噪声、非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种时，则所述CM用于确定所述载波外的侵入噪声、白噪声、非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种发生在所述方向选择性装置的输入端口侧。
可选的，所述方向选择性装置还用于：将从所述输入端口进入的由CMTS 发送给所述CM的下行信号通过所述分支端口传输给所述CM；以及，将从所述分支端口进入的由所述CM发送给所述CMTS的第三上行信号通过所述输入端口传输给所述CMTS。如此可以保证所述CM的业务的正常进行。
关于所述具备上行信号采集分析功能的CM和所述方向选择性装置的细节可参考上文的描述，在此不再赘述。
如图13所示，为将图6A所示的CM与图9A所示的方向选择性装置组合后的示意图。一种可能的HFC网络故障检测定位系统可以包括多个级联的如图13所示的结构。所述系统可以综合所述多个如图13所示的结构中的CM关于是否存在故障以及存在何种故障的判断结果，在HFC网络中定位可能发生故障的位置。
例如，假设图1中的所有CM为本申请中具备上行信号采集分析功能的CM，图1中的所有Tap为本申请中的方向选择性装置，且这些Tap只让来自下游的上行信号流入到其分支端口，那么只要某个CM探测到了故障，则可以确定该故障发生在该CM的下游；而如果某个故障发生在某个CM的上游，该CM是无法探测到该故障的。如，图1中，当只有CM1探测到了侵入噪声而其它CM均未探测到侵入噪声时，可以确定该侵入噪声发生在CM2处。又如，当CM1和CM2探测到了脉冲噪声而其他CM均未探测到脉冲噪声时，可以确定该脉冲噪声发生在CM3、CM4和CM5中的一个或多个中，后续CM3、CM4和CM5通过强度检测，可以进一步确定是哪个或哪些CM产生了脉冲噪声。
基于上述提供的具备上行信号采集分析功能的CM，本申请还提供了一种故障检测方法，如图14所示，所述方法包括以下步骤：
步骤141：CM采集来自所述CM的下游的上行信号，或采集来自所述CM的上游的上行信号，或采集来自所述CM的上游和下游混合的上行信号。
步骤142：所述CM检测所述上行信号是否存在非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种。
可选的，所述CM在采集来自CM的下游的上行信号，或采集来自所述CM的上游的上行信号，或采集来自所述CM的上游和下游混合的上行信号时，可 以有以下三种方式：
第一，所述CM根据CMTS下发的上行带宽分配映射消息，确定空时隙或静默探测信号对应的时间间隔，并在所述空时隙或静默探测信号对应的时间间隔内采集所述上行信号，所述上行带宽分配映射消息消息用于指示所述CMTS管辖下的各个CM分别占用的时隙，所述空时隙或静默探测信号表示不被任何CM占用的时隙。
第二，所述CM根据所述CMTS下发的上行带宽分配映射消息消息，确定所述CM的上游设备或所述CM的下游设备中的任一个设备的业务标识SID，并在所述任一个设备的SID对应的时间间隔内采集所述上行信号。
第三，所述CM随机采集所述上行信号。
可选的，所述CM在检测所述上行信号是否存在非线性失真时，可以根据所述上行信号的时域采样值绘制直方图；若绘制的所述直方图不符合高斯分布，则所述CM确定所述上行信号存在非线性失真。
可选的，所述CM在所述采集来自CM的下游的上行信号，或采集来自所述CM的上游的上行信号，或采集来自所述CM的上游和下游混合的上行信号之后，所述CM可以采集通过带通滤波器后的所述上行信号，或者也可以采集所述上行信号后再将采集的所述上行信号输入所述带通滤波器进行处理，所述带通滤波器的中心频点在所述CM的上行工作频段之外。
相应的，所述CM在检测所述上行信号是否存在脉冲噪声时，若所述带通滤波器的通带内的能量达到设定的阈值，则所述CM可以确定所述上行信号存在脉冲噪声。
可选的，所述CM在所述空时隙或静默探测信号对应的时间间隔内采集所述上行信号之后，若所述CM采集到所述上行信号，则所述CM可以通过频谱分析确定所述上行信号是否存在载波下的侵入噪声。
可选的，所述CM在所述任一个设备的SID对应的时间间隔内采集所述上行信号之后，所述CM可以确定所述上行信号是否存在线性失真。
可选的，所述CM在所述任一个设备的SID对应的时间间隔内采集所述上 行信号之后，所述CM还可以解调所述上行信号，得到所述上行信号的信号质量参数，所述信号质量参数包括均衡系数，MER和电平；和/或，所述CM获取所述任一个设备的测试信号；对比所述测试信号和所述上行信号，得到所述CM与所述任一个设备之间的线路传输特性；所述测试信号为所述上行信号从所述任一个设备发出时的初始状态信号。
综上所述，本申请提供的技术方案，一方面对常规的CM进行改造，让CM不仅可以检测载波外的侵入噪声和白噪声，还可以检测非线性失真、脉冲噪声、载波下的侵入噪声和线性失真等其它故障问题，并且CM在检测故障的同时不会影响业务的进行。另一方面，本申请对常规的Tap进行改造，使得Tap具有方向选择性，可以只让从Tap的输出端口进入的上行信号传输到该Tap的分支端口连接的CM，而不让从该Tap的输入端口进入的上行信号传输到该Tap的分支端口连接的CM，从而一旦该CM从上行信号中检测到故障，能够准确地定位出HFC网络中发生故障的位置在该Tap的输出端口侧；或者，该Tap也可以只让从Tap的输入端口进入的上行信号传输到该Tap的分支端口连接的CM，而不让从该Tap的输出端口进入的上行信号传输到该Tap的分支端口连接的CM，从而一旦该CM从上行信号张检测到故障，能够准确地定位出HFC网络中发生故障的位置在该Tap的输入端口侧。
本领域内的技术人员应明白，本发明的实施例可提供为方法、系统、或计算机程序产品。因此，本发明可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本发明可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。
本发明是参照根据本发明实施例的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通 过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。
尽管已描述了本发明的优选实施例，但本领域内的技术人员一旦得知了基本创造性概念，则可对这些实施例作出另外的变更和修改。所以，所附权利要求意欲解释为包括优选实施例以及落入本发明范围的所有变更和修改。
显然，本领域的技术人员可以对本发明实施例进行各种改动和变型而不脱离本发明实施例的精神和范围。这样，倘若本发明实施例的这些修改和变型属于本发明权利要求及其等同技术的范围之内，则本发明也意图包含这些改动和变型在内。

Claims (20)

  1. 一种电缆调制解调器CM，其特征在于，包括：
    采集模块，用于采集来自所述CM的下游的上行信号，或采集来自所述CM的上游的上行信号，或采集来自所述CM的上游和下游混合的上行信号；
    所述分析模块，用于检测所述上行信号是否存在非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种。
  2. 如权利要求1所述的CM，其特征在于，所述采集模块在采集所述上行信号时，具体用于：
    根据同轴电缆局端接入设备CMTS下发的上行带宽分配映射消息，确定空时隙或静默探测信号对应的时间间隔，并在所述空时隙或静默探测信号对应的时间间隔内采集所述上行信号，所述上行带宽分配映射消息消息用于指示所述CMTS管辖下的各个CM分别占用的时隙，所述空时隙或静默探测信号表示不被任何CM占用的时隙；或
    根据所述CMTS下发的上行带宽分配映射消息消息，确定所述CM的上游设备或所述CM的下游设备中的任一个设备的业务标识SID，并在所述任一个设备的SID对应的时间间隔内采集所述上行信号；或
    随机采集所述上行信号。
  3. 如权利要求1或2所述的CM，其特征在于，所述分析模块在检测所述上行信号是否存在非线性失真时，具体包括：
    根据所述上行信号的时域采样值绘制直方图；
    若绘制的所述直方图不符合高斯分布，则确定所述上行信号存在非线性失真。
  4. 如权利要求1或2所述的CM，其特征在于，所述采集模块还包括带通滤波器；
    所述采集模块采集通过所述带通滤波器后的所述上行信号；或，所述采集模块采集所述上行信号后将采集的所述上行信号输入所述带通滤波器进行 处理；
    所述带通滤波器的中心频点在所述CM的上行工作频段之外；
    所述分析模块在检测所述上行信号是否存在脉冲噪声时，具体包括：
    若所述带通滤波器的通带内的能量达到设定的阈值，则确定所述上行信号存在脉冲噪声。
  5. 如权利要求2所述的CM，其特征在于，所述采集模块在所述空时隙或静默探测信号对应的时间间隔内采集所述上行信号；
    所述分析模块具体用于：
    若所述采集模块采集到所述上行信号，则通过频谱分析确定所述上行信号是否存在载波下的侵入噪声。
  6. 如权利要求2所述的CM，其特征在于，所述采集模块在所述任一个设备的SID对应的时间间隔内采集所述上行信号；
    所述分析模块具体用于：
    确定所述上行信号是否存在线性失真。
  7. 如权利要求6所述的CM，其特征在于，所述分析模块还用于：
    解调所述上行信号，得到所述上行信号的信号质量参数，所述信号质量参数包括均衡系数，调制误差比MER和电平；和/或
    获取所述任一个设备的测试信号；对比所述测试信号和所述上行信号，得到所述CM与所述任一个设备之间的线路传输特性；所述测试信号为所述上行信号从所述任一个设备发出时的初始状态信号。
  8. 如权利要求1-7中任一项所述的CM，其特征在于，所述CM还包括接口，上行发送模块，下行接收模块和双工器；
    所述双工器与所述接口相连，所述双工器中的低通滤波器与所述上行发送模块相连，所述双工器中的高通滤波器与所述下行接收模块相连；
    所述采集模块和所述分析模块位于所述双工器与所述接口之间的线路的分支上；或，所述采集模块和所述分析模块位于所述双工器与所述上行发送模块之间的线路的分支上。
  9. 如权利要求1-7中任一项所述的CM，其特征在于，所述CM还包括接口，上行发送模块，下行接收模块和环形器；
    所述环形器的三个端口分别与所述接口、所述上行发送模块和所述下行接收模块相连，从所述接口进入的信号经过所述环形器后到达所述下行接收模块，所述上行发送模块发送的信号经过所述环形器后从所述接口发出；
    所述采集模块和所述分析模块位于所述环形器与所述下行接收模块之间的线路的分支上；或，所述采集模块和所述分析模块位于所述下行接收模块的内部。
  10. 一种混合光纤同轴电缆网络故障定位系统，其特征在于，包括如权利要求1-9中任一项所述的电缆调制解调器CM，还包括方向选择性装置，所述方向选择性装置包括分支端口、输入端口和输出端口，所述CM与所述方向选择性装置的分支端口相连；所述方向选择性装置的输入端口连接所述CM的上游，所述方向选择性装置的输出端口连接所述CM的下游；
    所述方向选择性装置，用于将从所述输出端口进入的来自所述CM的下游的第一上行信号通过所述分支端口传输给所述CM，以及隔离从所述输入端口进入的来自所述CM的下游的第二上行信号，使得所述第二上行信号无法到达所述CM；或，用于将所述第二上行信号通过所述分支端口传输给所述CM，以及隔离所述第一上行信号，使得所述第一上行信号无法到达所述CM；
    若所述方向选择性装置选择将所述第一上行信号传输给所述CM以及隔离所述第二上行信号，则当所述CM检测到所述第一上行信号存在非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种时，所述CM用于确定所述非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种发生在所述方向选择性装置的输出端口侧；
    若所述方向选择性装置选择将所述第二上行信号传输给所述CM以及隔离所述第一上行信号，则当所述CM检测到所述第二上行信号存在非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种时，则所述CM用于确定所述非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至 少一种发生在所述方向选择性装置的输入端口侧。
  11. 如权利要求10所述的系统，其特征在于，所述方向选择性装置还用于：
    将从所述输入端口进入的由同轴电缆局端接入设备CMTS发送给所述CM的下行信号通过所述分支端口传输给所述CM；以及
    将从所述分支端口进入的由所述CM发送给所述CMTS的第三上行信号通过所述输入端口传输给所述CMTS。
  12. 如权利要求10所述的系统，其特征在于，所述方向选择性装置将所述第一上行信号传输给所述CM，以及隔离所述第二上行信号时，所述方向选择性装置还包括第一分支器、环形器、第一双工器、第二分支器和第二双工器；
    所述输出端口，用于将所述第一上行信号通过所述第一分支器的分支链路发送至所述环形器；
    所述环形器，用于将所述第一上行信号单向传输至所述第一双工器中的低通滤波器；
    所述第一双工器中的低通滤波器，用于将所述第一上行信号通过所述分支端口传输给所述CM；
    所述输入端口，用于将所述第二上行信号通过所述第二分支器的分支链路发送至所述第二双工器；
    所述第二双工器，用于将所述第二上行信号通过所述第二双工器中的低通滤波器发送至所述环形器；
    所述环形器还用于，将所述第二上行信号单向传输至所述第一分支器，由所述第一分支器将所述第二上行信号通过所述第一分支器的分支链路发送至所述输出端口发出。
  13. 如权利要求10所述的系统，其特征在于，所述方向选择性装置将所述第一上行信号传输给所述CM，以及隔离所述第二上行信号时，所述方向选择性装置还包括第一分支器、第一隔离器、分配器、第二隔离器、第一双工 器、第二分支器和第二双工器；
    所述输出端口，用于将所述第一上行信号通过所述第一分支器的分支链路发送至所述第一隔离器；
    所述第一隔离器，用于将所述第一上行信号单向传输至所述分配器；
    所述分配器，用于将所述第一上行信号传输至所述第一双工器中的低通滤波器；
    所述第一双工器中的低通滤波器，用于将所述第一上行信号通过所述分支端口传输给所述CM；
    所述输入端口，用于将所述第二上行信号通过所述第二分支器的分支链路发送至所述第二双工器；
    所述第二双工器，用于将所述第二上行信号通过所述第二双工器中的低通滤波器发送至所述第二隔离器；
    所述第二隔离器，用于阻止所述第二上行信号进入所述分配器。
  14. 一种故障检测方法，其特征在于，包括：
    电缆调制解调器CM采集来自所述CM的下游的上行信号，或采集来自所述CM的上游的上行信号，或采集来自所述CM的上游和下游混合的上行信号；
    所述CM检测所述上行信号是否存在非线性失真、脉冲噪声、载波下的侵入噪声和线性失真中的至少一种。
  15. 如权利要求14所述的方法，其特征在于，所述CM采集来自CM的下游的上行信号，或采集来自所述CM的上游的上行信号，或采集来自所述CM的上游和下游混合的上行信号，包括：
    所述CM根据同轴电缆局端接入设备CMTS下发的上行带宽分配映射消息，确定空时隙或静默探测信号对应的时间间隔，并在所述空时隙或静默探测信号对应的时间间隔内采集所述上行信号，所述上行带宽分配映射消息消息用于指示所述CMTS管辖下的各个CM分别占用的时隙，所述空时隙或静默探测信号表示不被任何CM占用的时隙；或
    所述CM根据所述CMTS下发的上行带宽分配映射消息消息，确定所述CM的上游设备或所述CM的下游设备中的任一个设备的业务标识SID，并在所述任一个设备的SID对应的时间间隔内采集所述上行信号；或
    所述CM随机采集所述上行信号。
  16. 如权利要求14或15所述的方法，其特征在于，所述CM检测所述上行信号是否存在非线性失真，包括：
    所述CM根据所述上行信号的时域采样值绘制直方图；
    若绘制的所述直方图不符合高斯分布，则所述CM确定所述上行信号存在非线性失真。
  17. 如权利要求14或15所述的方法，其特征在于，在所述CM采集来自CM的下游的上行信号，或采集来自所述CM的上游的上行信号，或采集来自所述CM的上游和下游混合的上行信号之后，所述方法还包括：
    所述CM采集通过带通滤波器后的所述上行信号；或，所述CM采集所述上行信号后将采集的所述上行信号输入所述带通滤波器进行处理；所述带通滤波器的中心频点在所述CM的上行工作频段之外；
    若所述带通滤波器的通带内的能量达到设定的阈值，则所述CM确定所述上行信号存在脉冲噪声。
  18. 如权利要求15所述的方法，其特征在于，所述CM在所述空时隙或静默探测信号对应的时间间隔内采集所述上行信号之后，所述方法还包括：
    若所述CM采集到所述上行信号，则所述CM通过频谱分析确定所述上行信号是否存在载波下的侵入噪声。
  19. 如权利要求15所述的方法，其特征在于，所述CM在所述任一个设备的SID对应的时间间隔内采集所述上行信号之后，所述方法还包括：
    所述CM确定所述上行信号是否存在线性失真。
  20. 如权利要求19所述的方法，其特征在于，所述CM在所述任一个设备的SID对应的时间间隔内采集所述上行信号之后，所述方法还包括：
    所述CM解调所述上行信号，得到所述上行信号的信号质量参数，所述 信号质量参数包括均衡系数，调制误差比MER和电平；和/或
    所述CM获取所述任一个设备的测试信号；对比所述测试信号和所述上行信号，得到所述CM与所述任一个设备之间的线路传输特性；所述测试信号为所述上行信号从所述任一个设备发出时的初始状态信号。
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