Abstract: Methods and systems capable of improving the transmission of data along an upstream path of a Hybrid Fiber-Coaxial Cable Network, from a transmitter in a node to a receiver in a Cable Modem Termination System.

Abstract: A coaxial cable tap comprises a housing, and a faceplate coupled to the housing. The faceplate comprises a first directional tap port, and a diagnostic reverse (DR) port configured to receive a first upstream signal originating downstream from the coaxial cable tap, and inject a downstream test signal in a downstream direction. A hybrid fiber-coaxial (HFC) network comprises a headend, a first amplifier coupled to the headend, and a tap coupled to the first amplifier, configured to couple to a plurality of cable modems (CMs), and comprising a diagnostic forward (DF) port configured to receive a downstream signal originating from the first amplifier, and inject an upstream test signal in an upstream direction for reception at the headend.

Abstract: A coaxial cable remote diagnostic management tool (RDMT) comprises a receiver configured to receive a first signal, wherein the first signal is a time domain signal; and receive an instruction to analyze the first signal; and a processor coupled to the receiver and configured to: generate a trigger based on the instruction; convert the first signal into a second signal, wherein the second signal is a frequency domain signal; perform a comparison of the trigger to the second signal; and process the second signal based on the comparison.

Abstract: A coaxial cable tap comprises a housing, and a faceplate coupled to the housing. The faceplate comprises a first directional tap port, and a diagnostic reverse (DR) port configured to receive a first upstream signal originating downstream from the coaxial cable tap, and inject a downstream test signal in a downstream direction. A hybrid fiber-coaxial (HFC) network comprises a headend, a first amplifier coupled to the headend, and a tap coupled to the first amplifier, configured to couple to a plurality of cable modems (CMs), and comprising a diagnostic forward (DF) port configured to receive a downstream signal originating from the first amplifier, and inject an upstream test signal in an upstream direction for reception at the headend.

Abstract: An automated method of characterizing distortion detected by equalization on a channel of a network is provided. Equalization stress of an observed channel equalization response of an end device of the network is estimated, and equalization stress is calculated for a theoretical channel equalization response of the end device mathematically based on the observed channel equalization response and a theoretical removal of a suspected impairment from the network. The above referenced calculating step is separately repeated for each of a plurality of suspected impairments stored in a database of suspected impairments. A highest ranking suspected dominant impairment is determined from the database of suspected impairments such that removal of the highest ranking suspected dominant impairment from the network would provide a greatest reduction of equalization stress of a channel equalization response of the end device.

Abstract: The dynamic range of an optical link in a network is determined by simultaneously transmitting signals from two network elements at first and second frequencies, which create a combined signal at a third frequency. The transmission power levels of selected network elements is successively increased until the measured power from the third frequency no longer changes in a predictable manner, at which point the upper limit of the dynamic range of the optical link is determined.

Abstract: An automated method of characterizing distortion detected by equalization on a channel of a network is provided. Equalization stress of an observed channel equalization response of an end device of the network is estimated, and equalization stress is calculated for a theoretical channel equalization response of the end device mathematically based on the observed channel equalization response and a theoretical removal of a suspected impairment from the network. The above referenced calculating step is separately repeated for each of a plurality of suspected impairments stored in a database of suspected impairments. A highest ranking suspected dominant impairment is determined from the database of suspected impairments such that removal of the highest ranking suspected dominant impairment from the network would provide a greatest reduction of equalization stress of a channel equalization response of the end device.

Abstract: Method and apparatus for characterizing an impulse noise impairment impacting communications over data links of a network are provided. A test signal comprising a bit stream of a predetermined bit sequence and packet size is configured and transmitted over the data links. The test signal is received, and the bit stream of the test signal as transmitted is compared to a bit stream of the test signal as received to identify differences in bit sequence. Thereafter, characteristics of the impulse noise impairment impacting communications between the data links are estimated based on the detected differences in bit sequence.

Abstract: Logical channels in a network are automatically be configured by using measured network parameters. The measured network parameters are determined in cooperation with the network elements without interruption of active communication services. The network parameters include upstream or downstream modulation error ratio (MER), upstream or downstream signal to noise ratio (SNR), upstream or downstream microreflections, upstream transmit level, downstream receive power level, cable modem type (DOCSIS 1.0,1.1,2.0), functional capabilities (e.g., VoIP, 256QAM, etc), network element location with in a cable plant (e.g., node location or amplifier cascade depth), network element manufacturer, or type of services provided by the network element (including telephony versus data). An interactive display is provided to an operator which enables analysis of communication parameters, including modulation profiles and channel performance.

Abstract: The presence of micro-reflections is determined in a network by determining micro-reflections from amplifier and diplex filter impedance mismatches and micro-reflections from drop cable impedance mismatches. The micro-reflections from impedance mismatches are determined by instructing network element to transmit a test signal at a first symbol rate and a first resolution for amplifier and diplex filter impedance mismatches and a second frequency with a second symbol rate and second resolution for micro-reflections from drop cable impedance mismatches. The tests are performed with several frequencies and the channels with the least micro-reflections are identified.

Abstract: Methods are described for identifying a dominant impairment on a communication channel impaired by an interference issue. The methods include systematic examination of total power loading, systematic examination of signal power reduction, statistical examination of communication channel noise power, and systematic examination of interleaver effectiveness. Each relates to automatically diagnosing and characterizing distortion-based interference issues by monitoring the performance of a communication channel during a testing procedure. These methods enable a technician or engineer to remotely diagnose distortion-based interference issues relatively quickly without having to use external test equipment and without having to deploy technicians to various locations within the cable plant. A system by which these methods can be implemented is also disclosed.

Abstract: Methods are described for identifying a dominant impairment on a communication channel impaired by an interference issue. The methods include systematic examination of total power loading, systematic examination of signal power reduction, statistical examination of communication channel noise power, and systematic examination of interleaver effectiveness. Each relates to automatically diagnosing and characterizing distortion-based interference issues by monitoring the performance of a communication channel during a testing procedure. These methods enable a technician or engineer to remotely diagnose distortion-based interference issues relatively quickly without having to use external test equipment and without having to deploy technicians to various locations within the cable plant. A system by which these methods can be implemented is also disclosed.

Abstract: The available modulation schemes of a network are analyzed to determine which ones contain excessive phase noise or narrowband interference. A network element is selected and assigned to a test channel at a first modulation scheme at a predetermined power level to achieve a predetermined PER. The network element transmits a test signal and the network controller measures the signal to noise ratio (SNR) in the received test signal. If the SNR is not within a predetermined tolerance range of an estimated SNR for the modulation scheme at the predetermined PER, the modulation scheme is determined to have excessive phase noise or narrowband interference. Each available modulation scheme is tested by instructing the network element to transmit the test signal using each modulation scheme and assigning the power level of each modulation scheme. The suitable modulation schemes may be determined.

Abstract: Methods are described for identifying a dominant impairment on a communication channel impaired by an interference issue. The methods include systematic examination of total power loading, systematic examination of signal power reduction, statistical examination of communication channel noise power, and systematic examination of interleaver effectiveness. Each relates to automatically diagnosing and characterizing distortion-based interference issues by monitoring the performance of a communication channel during a testing procedure. These methods enable a technician or engineer to remotely diagnose distortion-based interference issues relatively quickly without having to use external test equipment and without having to deploy technicians to various locations within the cable plant. A system by which these methods can be implemented is also disclosed.

Abstract: Methods are described for identifying a dominant impairment on a communication channel impaired by an interference issue. The methods include systematic examination of total power loading, systematic examination of signal power reduction, statistical examination of communication channel noise power, and systematic examination of interleaver effectiveness. Each relates to automatically diagnosing and characterizing distortion-based interference issues by monitoring the performance of a communication channel during a testing procedure. These methods enable a technician or engineer to remotely diagnose distortion-based interference issues relatively quickly without having to use external test equipment and without having to deploy technicians to various locations within the cable plant. A system by which these methods can be implemented is also disclosed.

Abstract: The present methods and systems provide spectrum management for enhancing upstream performance for cable networks. According to one embodiment, a method of enhancing upstream performance in a cable network includes the steps of measuring performance of an upstream channel at a first data signaling rate; determining whether the upstream channel supports a second data signaling rate based on the performance; and selectively transitioning to the second data signaling rate based on said determination. The second data signaling rate is a higher rate than the first data signaling rate.

Abstract: The available modulation schemes of a network are analyzed to determine which ones contain excessive phase noise or narrowband interference. A network element is selected and assigned to a test channel at a first modulation scheme at a predetermined power level to achieve a predetermined PER. The network element transmits a test signal and the network controller measures the signal to noise ratio (SNR) in the received test signal. If the SNR is not within a predetermined tolerance range of an estimated SNR for the modulation scheme at the predetermined PER, the modulation scheme is determined to have excessive phase noise or narrowband interference. Each available modulation scheme is tested by instructing the network element to transmit the test signal using each modulation scheme and assigning the power level of each modulation scheme. The suitable modulation schemes may be determined.

Abstract: The dynamic range of an optical link in a network is determined by simultaneously transmitting signals from two network elements at first and second frequencies, which create a combined signal at a third frequency. The transmission power levels of selected network elements is successively increased until the measured power from the third frequency no longer changes in a predicatable manner, at which point the upper limit of the dynamic range of the optical link is determined.

Abstract: A method and an apparatus are employed for individually monitoring the connectivity status of cables connected at a cable modem termination system (CMTS), where the cables conduct upstream and downstream RF communication signals. The monitoring is self-contained within the CMTS. The monitoring is achieved by producing a reference signal having a frequency outside the frequency range of the RF communication signals. The reference signal is injected onto the RF communication signal. The power level of the reference signal is detected within the CMTS, whereby the power level correlates with an expected cable load impedance. A DC control voltage based on the detected power level of the reference signal is generated, which allows a controller to determine the connectivity statuses of the connected cables.

Abstract: A cable interface system for a high availability, high frequency cable network. An example embodiment includes a Radio Frequency Matrix Switch which connects N cable head ends with N+1 Cable Modem Termination Systems by a set of coaxial cables having 75 ohm BNC connectors in the forward path and 75 ohm connectors in the return path. Push-on type connectors along with reduced size connectors and cables provide increased access to connection points on interface panels. Angled interface panels on the Radio Frequency Matrix Switch provide increased connector space. Grouping of connection points on a the Radio Frequency Matrix Switch simplifies installation and replacement of cables. The Radio Frequency Matrix Switch can immediately switch a spare Cable Modem Termination System into service as necessary to avoid down time.