General Instrument Corporation

Motorola Mobility LLC

Arris Enterprises LLC

Andrew Wireless Systems Gmbh

Arris Technology, Inc.

General Instrument Corporation of Delaware

Arris International IP Ltd

John L Moran

Michael Jaimie Cooper

Charles S Moore

Robert J Thompson

Charles Sidney Moore

Marc L Morrissette

Brian K Thibeault

Rudolph J Menna

Mark L Fowler

David J Smentek

Wei-Hung Hui

Thomas R Keske

Veronica M Lobo

Poth Boontor

William C Hart

A method and apparatus for updating equalization coefficients of an adaptive pre-equalizer of a network element are provided. The method includes monitoring a communications channel to measure distortion of a communications signal received from the network element and detecting whether a transient impairment is present in the communication signal. When a transient impairment is not detected to be present, a pre-equalization coefficient update is transmitted to the network element. However, when a transient impairment is detected to be present, at least selected ones of the pre-equalization coefficients are scaled before the update is transmitted to the network element or the update is withheld from being transmitted to the network element. An apparatus is also disclosed.

Method and apparatus for updating equalization coefficients of adaptive pre-equalizers

A system estimates impairment contributions for upstream communications in a cable television system. The system receives equalization coefficients used by end devices in the cable television system. The equalization coefficients are used by equalizers to mitigate distortion in upstream channels for the end devices. The system analyzes the coefficients based on impairment thresholds to determine whether impairment problems exist and to identify the types of impairment problems that exist.

Using equalization coefficients of end devices in a cable television network to determine and diagnose impairments in upstream channels

Instability resulting from non-linear impairments is detected and an equalizer of an end device is reset. An equalization instability threshold is retrieved from a data storage device. An equalization parameter for the end device is monitored and, if the equalization parameter exceeds the equalization instability threshold, the equalizer is reset.

Monitoring instability and resetting an equalizer

A network element is identified from among a plurality of network elements to be used to test parameters of a network. The use of one network element to test the network provides more reliable results than using random communications from a plurality of network elements. The test network element is identified using testing pool definitions which may be provided by a network operator. The testing procedure using the single network element may use multiple pings to reduce the affect of transient responses on the network.

Method and apparatus for selecting a network element for testing a network

A logical channel is configured to match a modulation profile of an active channel. A network element is assigned to the logical channel and a ping request is sent to the network element. A response from the network element is measured, such as measuring the MER. The modulation profile is increased in the logical channel and another ping request is sent to the network element. The response is measured again, and the process is repeated until a non-linearity is detected in the response. The acceptable modulation profiles are indicated before the non-linearity is detected in the response.

Method and apparatus for determining modulation levels that are supported on a channel

Network elements are identified as being connected to optical nodes by instructing two network elements in a spectrum group of the CMTS to transmit at frequencies fand f, respectively. Frequencies fand fare selected such that they produce intermodulation distortions (intermods) in the laser transmitter at fwhen combined. If intermods are produced which exceed a predetermined threshold, then the two network elements are determined to be on the same node. If the total power of the signal by the laser transmitter exceeds an impact threshold, then the test is stopped and new network elements are selected for testing.

Efficient use of trusted third parties for additional content-sharing security

Preamble length of burst communication signals dynamically changed to compensate in changes to linear distortion of a communication channel. Pre-equalization coefficients are provided to network element which pre-equalize communications with the CMTS. Long preamble lengths are used for a select few communications while short preamble lengths are used for the rest of the communication signals. When change in distortion characteristics is detected, a station maintenance is performed on the affected network element and new pre-equalization coefficients are determined and provided to the network element. Alternatively, all communications may be provided with long preamble lengths and communications may continue while the CMTS determines new pre-equalization coefficients.

Method and apparatus for dynamically changing the preamble length of a burst communication

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John L Moran