Distributed Network Performance Monitoring
A probe is configured to monitor one or more communication parameters on one or more downstream frequency channels carried on a communication medium of an access network. Results of repeated monitoring are stored over a predetermined period. At the conclusion of the monitoring period, data reports reflecting the stored results are transmitted in upstream frequency channels carried on the same medium. The probe can also be configured to send immediate messages if a parameter exceeds predefined limits and can store a plurality of monitoring programs and can be reprogrammed remotely. The probe can be contained within a cable tap if the medium is, e.g., a coaxial cable. Numerous probes can be deployed throughout an access network so as to provide monitoring data from each of many locations over a prolonged period.
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In addition to cable television (CATV), many cable system operators provide high speed internet access, video on demand (VOD), Voice over IP (VoIP) telephone and numerous other services to subscribers. To provide such services, cable system operators must manage and maintain increasingly complex networks.
From the hubs, individual homes or other subscriber locations are reached via a hybrid fiber coax (HFC) access network. The fiber optic portion of the HFC access network includes multiple nodes on a fiber optic ring. The coaxial portion of the HFC access network includes coaxial feeder lines extending from those nodes. Drop coaxial cables extend from taps in the feeder cables and connect to the subscriber premises. Amplifiers are distributed along the coaxial feeder cables. Alternating current (AC) power may also be input into the feeder cables so as to provide a power source for the amplifiers. For simplicity,
Communication through a coaxial cable can be affected in many ways. As but one example, temperature changes can affect signal quality in coaxial cables. To detect, prevent and correct communication problems, signal quality measurements from the coaxial part of an HFC network can be very useful. Unfortunately, obtaining such measurements for a large portion of a coaxial cable network over a prolonged period has not been practical. Existing test equipment is relatively expensive, and in many cases a field service technician must be dispatched to take measurements. Some set top boxes and cable modems can measure certain signal parameters, but only over a few channels at a time and at relatively infrequent intervals. Moreover, signal measurements from inside a subscriber premises may not be indicative of a network problem. For example, signal degradation within a subscriber location could be affected by a splitter or other subscriber-installed component and not by a systemic network condition.
SUMMARYThis Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the invention.
At least some embodiments include a probe that can be installed in a desired location in an access network. In certain embodiments, a probe can be installed in a coaxial cable plant of an access network. The probe is configured to monitor one or more communication parameters on one or more downstream frequency channels carried on a physical medium such as a coaxial cable. Results of repeated monitoring are stored over a predetermined period. At the conclusion of the monitoring period, data reports reflecting the stored results are transmitted in upstream frequency channels carried on the same medium. The probe can also be configured to send immediate messages if a parameter exceeds predefined limits. The probe can store a plurality of monitoring programs and can be reprogrammed remotely. In some embodiments, the probe is contained within a cable tap. Numerous probes can be deployed throughout a coaxial cable plant so as to provide monitoring data from each of many locations over a prolonged period.
Some embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements.
In at least some embodiments, numerous probes throughout a coaxial cable plant monitor communication parameters. As used herein “coaxial cable plant” refers to the portion of an access network that transmits signals over coaxial cable. Some of the parameters measured by the probes are indicative of signal quality in the coaxial cable plant (e.g., RF signal level, modulation error ratio, etc.). Some parameters are indicative of whether a particular data payload (e.g., data for one or more programming services such as HBO, ESPN, etc.; a specific advertisement; a governmentally-required emergency message; etc.) has been transmitted. Each probe is coupled to a coaxial cable, monitors signals on that cable, and reports monitoring data upstream over the same coaxial cable. Because the probes in at least some embodiments are relatively inexpensive and automated, they can be widely deployed and provide data over prolonged periods of time. The probes can also be remotely controlled and/or reprogrammed to provide specific data when needed. In at least some embodiments, and as described in further detail below, the probes are sized and configured for attachment to one of the drop outputs of a cable tap. In other embodiments, the probes are housed within a tap.
In a typical cable system, coaxial cable carries communications in frequencies that may be as low as 5 MHz and as high as 1002 MHZ (or higher). In many systems, frequency channels in the lower portion of the available frequency spectrum are used to carry upstream communications from subscriber devices to the hub. Higher frequency channels are used to carry downstream communications from the hub to subscriber devices. The downstream frequency channels usually have bandwidths of 6 MHz or 8 MHz, although upstream channels may use narrower bands.
In at least some cable systems, most upstream and downstream communications with a subscriber device over a coaxial cable are in accordance with the set of standards known as Data over Cable Service Interface Specifications (DOCSIS) promulgated by (and available from) from Cable Television Laboratories, Inc. of Louisville, Colo. Under the latest version of the applicable DOCSIS standard, downstream 6 MHz or 8 MHz channels can be distributed between 108 MHz and 1002 MHz and upstream channels are located between 5 MHz and 42 (or 85) MHz. Frequency channels between these two regions are used for non-DOCSIS communications (e.g., legacy analog CATV programming). Upstream frequency channels and at least the downstream frequency channels above 108 MHz are typically modulated using quadrature amplitude modulation (QAM).
Downstream frequency channels can be used to communicate many types of data. For example, some downstream channels may be used to send generic user data payloads (e.g., data from an Internet site to which a subscriber has navigated, an email, a downloaded file, etc.) to a subscriber cable modem (CM) for further communication to a home computer. As another example, some downstream channels may be used to transmit digital video data payloads to a subscriber set top box (STB) for ultimate display on a television. Some channels may transmit several types of data by, e.g., interspersing packets containing digital video with packets containing generic user data. To accommodate multiple possible data types in a downstream channel, the DOCSIS standards require that downstream data packets be contained in 188-byte Moving Picture Expert Group (MPEG) packets. Each MPEG packet has a 4-byte header that includes a 13-bit packet identifier (PID) indicating the type of data contained in the MPEG packet. Generic user data and DOCSIS media access control (MAC) management messages are contained in one or more MAC frames that follow the 4-byte MPEG header, with each MAC frame also having its own MAC header.
Hardware interface 11 is connected to a diplexer 12 that allows downstream signals to pass into probe 10 and upstream signals to pass out of probe 10. Downstream signals flow from diplexer 12 to a wideband tuner 14. In response to a control signal from controller 16 identifying a frequency channel to be tuned, tuner 14 forwards a signal for the tuned frequency channel. In some embodiments, tuner 14 is a single wideband tuner that is able to selectively tune to any frequency channel between 108 MHz and 1002 MHz. In other embodiments, tuner 14 is able to tune to channels below 108 MHz and/or above 1002 MHz. In still other embodiments, tuner 14 can be replaced with multiple tuners that tune across narrower bands.
In at least some embodiments, main processor 15 is a single application specific integrated circuit (ASIC) having signal analysis circuits and programmable logic for performing operations as described herein. These circuits and logic are represented by functional blocks 16 through 18 for purposes of explanation. Controller 16 contains logic for executing instructions that control the operation of main processor 15 and tuner 14. Controller 16 also executes instructions to perform more advanced signal and/or data analysis. For example, and as described below, controller 16 is in some embodiments configured to examine specific data fields within a MPEG transport packet or a digital video payload packet and determine if specific packets have been received. In addition to hard-wired instructions, controller 16 reads instructions stored in one or more memories 19 or 20 and executes those instructions. Memories 19 and 20 may include non-volatile read-only memory (ROM), volatile random access memory (RAM) and non-volatile read/write memory (e.g., FLASH memory). Fully and/or partially programmable microprocessor circuits for performing the herein-described operations of controller 16 (and other portions of main processor 15) are either known in the art or can be readily constructed by persons of ordinary skill in the art once such persons are provided with the information contained herein. In some embodiments, the tuner 14, diplexer 12 and/or memory 20 may be included on the same ASIC chip with main processor 15.
The signal from tuner 14 is initially processed by DOCSIS PHY/MAC sub-processor 17. SUB-processor 17 includes a demodulator and processes the QAM physical (PHY) and DOCSIS media access control (MAC) layers. With regard to downstream communication, for example, DOCSIS PHY/MAC sub-processor 17 demodulates QAM signals, performs forward error correction (FEC) decoding and deinterleaving, reads MPEG transport stream headers to identify packets as DOCSIS MAC packets or digital video packets, extracts DOCSIS MAC payloads from MPEG packets containing DOCSIS MAC payloads, reads MAC headers and MAC management messages, etc. With regard to upstream communications from probe 10, DOCSIS PHY/MAC sub-processor 17 generates MAC management messages according to the DOCSIS MAC protocol, encapsulates data for transmission upstream according to the DOCSIS MAC protocol, performs error correction coding and interleaving, performs QAM modulation, etc. Additional DOCSIS PHY and MAC operations that are performed by a DOCSIS-compliant subscriber device are defined by the applicable DOCSIS standards, including but not limited to the following: DOCSIS 3.0 Physical Layer Specification (CM-SP-PHYv3.0-107-080522); DOCSIS 3.0 MAC and Upper Layer Protocols Interface Specification (CM-SP-MULPIv3.0408-080522); and Downstream RF Interface Specification (CM-SP-DRFI-I06-080215). In at least some embodiments, DOCSIS PHY/MAC sub-processor 17 is configured to perform all PHY and MAC operations that a conventional DOCSIS-compliant CM or STB can perform.
DOCSIS PHY/MAC sub-processor 17 measures some of the signal quality and other communications parameters, discussed in more detail below, for the tuned frequency channel. Sub-processor 17 then communicates these measurements and other data to controller 16 so that controller 16 may, e.g., store such data in memory 19 and/or memory 20 for additional analysis and/or later communication upstream. As represented by the double-headed arrow connecting blocks 16 and 17, sub-processor 17 also receives data and control signals from controller 16. The control signals and data sent to sub-processor 17 by controller 16 could include instructions to provide certain data or signal measurements, data and instructions to transmit that data in an upstream message, etc.
Persons of ordinary skill could, based on the above-identified DOCSIS standards and other known DOCSIS standards, and based on the information provided herein, include appropriate DOCSIS PHY and MAC circuits in an ASIC design for main processor 15. Indeed, numerous existing and commercially-available ASICs are designed to perform DOCSIS PHY and MAC layer functions. When provided with the information herein, persons of ordinary skill could incorporate the functionality of such existing ASIC designs into an ASIC that also includes the functionality of controller 16 and other elements of main processor 15 that are described herein.
In some embodiments, DOCSIS PHY/MAC sub-processor 17 also outputs a demodulated signal for additional analysis in signal analysis sub-processor 18, which includes additional circuits and logic for performing analyses to obtain desired data about downstream signals. In some embodiments, signal analysis sub-processor 18 may in some embodiments be dedicated to certain types of signal measurements that fall outside of normal DOCSIS PHY/MAC processing. Measurements and other data from signal analysis sub-processor 18 are provided to controller 16, which may store such measurements and data in memory 19 or memory 20 for additional analysis and/or later communication upstream.
In addition to receiving and analyzing downstream communications, main processor 15 sends reporting data and other communications upstream. Examples of such upstream communications, which pass from main processor 15 to diplexer 12 and hardware interface 11, are described below.
Finally, probe 10 includes a power supply circuit 23 that provides electrical operating power to main processor 15 and tuner 14. Power supply circuit 23 receives input power from a power source and converts that power to an appropriate form for main processor 15 and tuner 14. Power supply and conversion circuits are known in the art and thus are not further described herein. In some embodiments, and as explained below, circuit 23 receives input power from the AC power supplied in a coaxial feeder cable. In other embodiments, a probe power supply circuit may receive incoming power from a battery, from a conventional AC line source, or from some other source.
Probe 10 is configurable to measure or otherwise evaluate numerous signal, data and other communication parameters. Examples of such parameters are provided below. Circuits and logic for analyzing signals and data to measure or otherwise evaluate such parameters are known in the art or would be readily apparent to persons of ordinary skill in the art in view of the description provided herein.
In at least some embodiments, probe 10 is configured to monitor RF signal level on all downstream QAM channels on a regular basis. As is known in the art, RF signal strength in a coaxial cable plant is typically measured in decibel millivolts (dBmV), with 0 dBmV defined to represent a 1 mV signal on a 75 Ohm cable. RF signal level data can be extremely useful in many situations. For example, cable modems can tolerate an input signal between −15 dBmV and +15 dBmV, but performance is not uniform over this range. Optimal performance is often realized with input RF levels held between −6 dBmV to +15 dBmV. RF amplitude varies significantly over an HFC plant, however, and the amplitude variation is highly frequency dependent. Coaxial cable attenuates higher frequency carriers less than lower frequency carriers. So as to attain the correct signal level at the subscriber premises, coaxial feeder amplifiers and fiber nodes have both upstream and downstream PADs (passive attenuation devices) and equalizers to adjust signal level in different frequency ranges. Directional couplers and taps in the coaxial cable plant can also be chosen so as to have directional split and tap values that help keep the signal level reaching a subscriber premises at the correct level. Obtaining repeated RF signal levels on multiple frequency channels, from numerous locations in a coaxial cable plant, and over a prolonged period can provide data that is extremely useful for adjustment of PADs and equalizers and for adding (or replacing) taps, couplers, splitters and other components in the coaxial plant.
Additional parameters that can be measured by probe 10 for some or all channels include modulation error ratio (MER), FEC codeword error rate, signal to noise ratio (SNR), PLL lock, quantization noise (QN), and center frequency variation. As defined by DOCSIS, MER measures cluster variance (in dB) caused by a transmit waveform. MER includes effects of intersymbol interference, phase noise other transmitter degradations. FEC codeword error rate represents a ratio of the number of uncorrectable code words to the total number of code words sent without errors, with corrected errors and with uncorrectable errors. SNR, which represents the ratio (in dB) of usable signal to noise, can be defined and measured in any of various ways that are known in the art. PLL (phased lock loop) lock is a measurement of the ability of probe 10 to lock onto a carrier frequency for a given channel. QN represents is a measure of the relative noise figure when modulating a carrier. Center frequency variation represents the amount by which a particular frequency channel has varied from its assigned location in the downstream spectrum.
The above parameters are only some of the parameters that can be monitored by probe 10 according to various embodiments. Other examples of parameters that can be monitored by probe 10 include bit error rate (BER), the percentage of bits that have errors relative to the total number of bits received, and carrier-to-noise ratio (CNR), a ratio of signal power to noise power in the defined measurement bandwidth. Still another example includes errors in the program clock reference (PCR) in digital video MPEG packet streams which are measured by DOCSIS PHY/MAC sub-processor 17.
In some embodiments, probe 10 is also configurable to monitor the QAM constellation on a selected channel and to send a report providing a snapshot of the constellation. In certain embodiments, probe 10 is configured to compare a QAM constellation snapshot to a pattern stored in memory 20 and to report if the snapshot varies from the pattern by a predetermined amount.
In addition to communication parameters that are indicative of signal quality, probe 10 may also be configurable to monitor payload-specific communication parameters. As but one example, MPEG video packets can be examined to determine if digital watermarks or other data is present. In this manner, probe 10 can determine if particular content (e.g., an advertisement) has been broadcast. By way of further example, a cable company may sell advertising directed to localized markets. Content monitoring by multiple probes 10 located throughout coaxial plant portions of a cable system can provide data to confirm that advertising was broadcast at desired times, on the desired channel(s), and in the desired locations. In some embodiments, a probe may be further configured to record selected MPEG frames (e.g., selected I-frames and/or P-Frames) to provide additional confirmation of advertisement transmission. In such cases these frames could be recorded within probe 10 and transmitted upstream to a central server or other location for storage. Subsequently, an operator could spot check the stored frames to ensure that such frames were detected and recorded at the appropriate time as required by the advertisement.
As yet another example of monitorable data, probe 10 could also be configured to monitor DOCSIS set-top gateway (DSG) data and confirm that the proper services are being transmitted on the proper channels. For this monitoring, DOCSIS PHY/MAC sub-processor 17 could receive and decode DSG tunnels and extract payload data (e.g., SCTE 65 system information, SCTE 18 emergency alerts, etc.) to verify that such data has been sent and received within the plant.
As a further example of monitorable communication parameters, probe 10 could be configured to monitor the MPEG layer integrity of digital video and detect dropped packets, macroblocking (also known as “tiling”) and other types of service degradation. Additionally, probe 10 could monitor program clock reference (PCR) stamps to ensure completeness of programs, monitor program identifiers (PIDs) to ensure continuity, and monitor other MPEG-specific information to ensure correct transmission of video streams.
For example,
The cells in the next column of table 400 (“CF/BW”) contain data that is used by controller 16 to identify the center frequency (CF) and bandwidth (BW) for the channels on the corresponding rows. For simplicity, center frequency values are shown generically as “F” with a subscript matching the value of the CHAN variable on the same row. Similarly, bandwidth values are shown generically as “B” with a subscript matching the CHAN variable value of the CHAN variable on the same row. In some implementations, many of the channels will have the same value for B (e.g., 6 MHz for a DOCSIS downstream channel). In at least some embodiments, values for F and B can be reprogrammed so as to change monitored channels. A null value (e.g., all 0-bits) for the F and/or B variable(s) could be used to indicate that a channel is the last in the list.
Each of the remaining columns of table 400 corresponds to a different one of the communication parameters that can be monitored by probe 10. In the example of
Each of the cells in the PARAM value columns contains a time value representing a number of system clock increments or other suitable time units. In
For example, assume a cable system operator wishes to monitor RF level on channels 0-4 hourly, MER on channel 0 every 3 hours, and MER on channels 1 and 2 every 1.5 hours. The value of each of T(0,0), T(1,0), T(2,0), T(3,0) and T(4,0) is set to a number of time units corresponding to one hour, the value of T(0,1) is set to a number of time units corresponding to 3 hours, the value of T(1,1) and the value of T(2,1) are set to a number of time units corresponding to 1.5 hours, and all other T values in table 400 are set to the null value. The F and/or B value for channel 5 could also be set to a null value to indicate that only 5 channels are to be monitored, in which case the T values for channels 5 through c are irrelevant.
Returning to
Controller 16 then proceeds from block 204 to block 206. In block 206, controller 16 determines if the monitoring result for the parameter just monitored exceeds a predefined acceptable limit. This limit could also be stored in table 400 (
From block 208, or on the “no” branch from block 206 if the monitored parameter is not out of limits, controller 16 advances to block 210 and determines if the current parameter is the last parameter (e.g., PARAM=p in
In block 222, controller 16 determines if it has received a system interrupt message indicating that the current execution of the program corresponding to the
If the de-queued interrupt message indicates that it is time for a report, controller 16 proceeds to block 305 on the “yes” branch, where the report is prepared and sent. In some embodiments, and so as to conserve memory at probe 10, controller 16 is configured to erase stored monitoring data after receiving confirmation that the report was successfully received. From block 305, controller 16 proceeds to block 315. Block 315 is explained below.
If controller 16 determines in block 302 that the de-queued interrupt message was not an indication of a time to transmit a report, controller 16 proceeds on the “no” branch to block 306. In block 306, controller 16 determines whether the de-queued interrupt message is an indication that a new program is ready for download to probe 10. As previously indicated, memory 19 and/or memory 20 in some embodiments stores multiple programs executable by controller 16. Those programs can be stored in memory after installation of probe 10 by transmitting downstream data packets addressed to probe 10. If the de-queued interrupt message indicates that new programming is ready for download, controller 16 proceeds to block 307. In block 307, controller 16 downloads the new program(s) by, e.g., sending an upstream message indicating the probe is ready for download and then receiving additional downstream messages containing the new program(s).
A new program may, for example, be a new table that is similar to table 400 of
From block 307, controller 16 proceeds to block 308 and determines if a newly downloaded program includes instructions to immediately execute the new program. If so, controller 16 proceeds on the “yes” branch to block 310 and executes the new program. The new program may include an instruction to return to the algorithm of
If in block 306 controller 16 determined that the de-queued interrupt message was not an indication to download new programming, controller 16 would instead proceed on the “no” branch to block 313. In block 313, controller 16 determines if the de-queued interrupt message is an instruction to begin executing a program that is already stored in memory 19 or memory 20 of probe 10. In some embodiments, memory 20 stores a variety of tables similar to table 400 of
If controller 16 determines in block 313 that there is no instruction to start a specified program, controller 16 proceeds to determine if the de-queued interrupt message indicates another type of action to be taken. The presence of additional decisional blocks and corresponding actions is indicated generically in
The algorithm of
As indicated above, the algorithm of
In some embodiments, a time T stored in table 400 may also (or alternatively) include a specific time and/or date on which monitoring of a particular communication parameter is to begin. For example, table 400 may store data indicating that a probe is to begin monitoring parameter p at a particular time on a particular day and to continue monitoring that parameter every 30 minutes thereafter. As another example, table 400 may store data indicating that a probe is to begin monitoring parameter p at a first time on a particular day and to continue monitoring that parameter every 10 seconds until a second time on that same day.
Downstream messages to probe 10 and upstream messages from probe 10 can be formulated as DOCSIS MAC management messages and appropriate values assigned to one or more fields so as to mark messages as a program download, an instruction to change programs, an emergency parameter report, a routine monitoring report, etc. Additional types of instructions can also be provided to probe 10 in a downstream message (e.g., to change upstream channels used by probe 10 for reporting).
Monitoring data from the probes can be periodically reported to a central collection point and/or can be reported on demand. That collection point can be in the hub (e.g., incorporated into a CMTS), or monitoring data can be forwarded from a hub to another location (e.g., a management server) that collects monitoring data for multiple hubs. The monitoring data can be used to periodically evaluate system performance, to quickly detect equipment malfunctions, to diagnose reported problems, to determine if advertising or other content has been transmitted where and when intended, etc. In some embodiments, monitoring data from probes is also used to remotely adjust amplifiers, equalizers and PADs within a coaxial cable plant.
In some embodiments, a probe may include a temperature sensor to provide temperature data for calibration of the probe and/or for adjustment PADs, equalizers or other components to account for temperature-dependent effects on coaxial cable lines. The temperature sensor can also be periodically monitored and the results communicated to the central collection point.
The foregoing description of embodiments has been presented for purposes of illustration and description. The foregoing description is not intended to be exhaustive or to limit embodiments of the present invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments. As but one example, embodiments of the invention include one or more tangible machine-readable storage media storing instructions that, when executed by one or more processors or other devices, cause a probe to carry out operations such as are described herein. The embodiments discussed herein were chosen and described in order to explain the principles and the nature of various embodiments and their practical application to enable one skilled in the art to utilize the present invention in various embodiments and with various modifications as are suited to the particular use contemplated. The features of the embodiments described herein may be combined in all possible combinations of methods, apparatus, modules, systems, and machine readable media.
Claims
1. An apparatus comprising:
- a hardware connector configured for attachment to a physical communication medium of an access network;
- at least one tuner communicatively coupled to the hardware connector; and
- a processor communicatively coupled to the at least one tuner, wherein the processor is configured to monitor communication parameters in a first downstream frequency channel and store the results of the monitoring, monitor communication parameters in a second downstream frequency channel and store the results of the monitoring, and transmit the stored monitoring results for the first and second downstream frequency channels, on an upstream frequency channel carried on the physical communication medium, wherein the processor is configured to perform multiple repetitions of the monitoring for at least one of the first and second downstream frequency channels prior to transmitting the stored monitoring results, and the transmitted stored monitoring results include the monitoring results from the multiple repetitions.
2. The apparatus of claim 1, wherein the physical communication medium comprises a coaxial cable of a cable plant.
3. The apparatus of claim 2, wherein
- the processor is configured to monitor communication parameters on each of 10 downstream frequency channels and store the results from monitoring each of the 10 downstream frequency channels, and
- the transmitted stored monitoring results include the stored results from monitoring of the at least 10 downstream frequency channels.
4. The apparatus of claim 3, wherein the at least 10 downstream frequency channels are located between 108 MHz and 1002 MHz.
5. The apparatus of claim 2, wherein the communication parameters comprise RF signal level and at least one parameter selected from a group of parameters that includes modulation error ratio, forward error correction codeword error rate, signal to noise ratio, bit error rate and carrier to noise ratio.
6. The apparatus of claim 5, wherein monitoring communication parameters in the first and second downstream frequency channels comprises determining whether specific data has been transmitted.
7. The apparatus of claim 2, wherein monitoring communication parameters in the first and second downstream frequency channels comprises determining whether specific data has been transmitted.
8. The apparatus of claim 2, wherein the processor is configured to repeatedly measure a first communication parameter for each of the first and second downstream frequency channels according to a first schedule and to repeatedly measure a second communication parameter for each of the first and second downstream frequency channels according to a second schedule, and wherein the first schedule requires measurement of the first communication parameter more frequently than the second schedule requires measurement of the second communication parameter.
9. The apparatus of claim 2, wherein the hardware connector is a connector configured for attachment to a forward RF input coaxial feeder cable, and further comprising a plurality of connectors configured for attachment to coaxial drop cables.
10. The apparatus of claim 2, wherein the processor is configured to receive programming instructions, via the coaxial cable, causing the processor to
- monitor communication parameters in a third downstream frequency channel and store the results of the monitoring,
- monitor communication parameters in a fourth downstream frequency channel and store the results of the monitoring, and
- transmit the stored monitoring results for the third and fourth downstream channels subsequent to the monitoring of the communications parameters in third and fourth the fourth downstream frequency channels.
11. The apparatus of claim 1, wherein the processor is configured to download instructions, and wherein the downloaded instructions cause the processor to monitor a different communication parameter.
12. An cable tap, comprising:
- a housing;
- a feeder cable connector located on or attached to the housing and configured for attachment to a coaxial feeder cable of a cable plant;
- an RF signal line located within the housing and communicatively coupled to the feeder cable connector;
- a plurality of drop cable connectors, wherein each of the drop cable connectors is configured for attachment to a different coaxial drop cable and is communicatively coupled to the RF signal line;
- at least one tuner located within the housing and communicatively coupled to the RF signal line; and
- a processor located within the housing and communicatively coupled to the at least one tuner, wherein the processor is configured to cause the tuner to tune to a first downstream channel carried on the RF signal line, monitor a first communication parameter in the first downstream frequency channel and store the results of the monitoring, and transmit the stored monitoring results on an upstream frequency channel carried on the RF signal line.
13. The cable tap of claim 12, wherein
- the processor is configured to perform multiple repetitions of the monitoring for the first downstream frequency channel and for a second downstream frequency channel prior to transmitting the stored monitoring results, and
- the transmitted stored monitoring results include the monitoring results from the multiple repetitions.
14. The cable tap of claim 12, wherein
- the processor is configured to monitor the communication parameter on each of at least 10 downstream frequency channels and store the results from monitoring the communication parameter on each of the at least 10 downstream frequency channels, and
- the transmitted stored monitoring results include the stored results from monitoring of the at least 10 downstream frequency channels.
15. The cable tap of claim 14, wherein the at least 10 downstream frequency channels are located between 108 MHz and 1002 MHz.
16. The cable tap of claim 12, wherein the first communication parameter comprises RF signal level, and wherein the processor is further configured to monitor a second parameter selected from a group of parameters that includes modulation error ratio, forward error correction codeword error rate, signal to noise ratio, bit error rate and carrier to noise ratio, to store results of monitoring the second parameter, and to transmit the stored second parameter monitoring results upstream.
17. The cable tap of claim 16, wherein the processor is further configured to determine whether specific data has been transmitted downstream, to store the results of the determination, and to transmit the stored determination results upstream.
18. The cable tap of claim 12, wherein the first communication parameter comprises whether specific data has been transmitted.
19. A method, comprising:
- receiving communication parameter monitoring data from multiple probes distributed throughout a coaxial cable plant, wherein each of the probes is connected to the coaxial cable plant outside of a subscriber location, and each of the probes repeatedly monitors communication parameters on multiple downstream channels for a period of time, stores the results of the monitoring, and transmits the stored results upstream over the coaxial cable plant at the conclusion of the time period;
- transmitting instructions to a portion of the plurality of probes through the coaxial cable plant, said instructions changing the manner in which the portion of the plurality of probes monitors communication parameters; and
- receiving additional data from the portion of the plurality of probes in response to the transmitted instructions.
20. The method of claim 19, wherein at least a portion of the plurality of probes are contained within cable taps.
Type: Application
Filed: May 20, 2009
Publication Date: Nov 25, 2010
Applicant: COMCAST CABLE COMMUNICATIONS, LLC (Philadelphia, PA)
Inventors: Jorge Daniel Salinger (Littleton, CO), Maurice Garcia (Levittown, PA)
Application Number: 12/469,168
International Classification: H04N 7/173 (20060101); H01R 9/05 (20060101);