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

• US 20080200129A1
• Filed: 01/30/2008
• Published: 08/21/2008
• Est. Priority Date: 01/30/2007
• Status: Active Grant

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Inventors: Thompson, Robert J., Moran, John L., Moore, Charles S., Cooper, Michael J., Thibeault, Brian
• Granted Patent: US 8,265,559 B2
• Time in Patent Office: Days
• US Class Current: 455/67.14
• CPC Class Codes: G01R 29/06 Measuring depth of modulation
• CPC Class Codes: H04L 25/085 Arrangements for reducing interference in line transmission systems, e.g. by differential transmission
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/0012 arrangements for identifying the type of modulation
• CPC Class Codes: H04L 43/50 Testing arrangements
• CPC Class Codes: H04L 5/1453 of modulation type
• CPC Class Codes: H04N 17/004 for digital television systems
• CPC Class Codes: H04N 21/238 Interfacing the downstream path of the transmission network, e.g. adapting the transmission rate of a video stream to network bandwidth; Processing of multiplex streams hybrid fiber coaxial [HFC] networks for downstream channel allocation for video distribution H04L12/2801; flow control in packet networks H04L47/10; real-time communication protocols in data switching networks H04L65/00; scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04N 21/2383 Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/4382 Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002

Abstract

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.

Claims

1. An apparatus for monitoring a network comprising:

a microprocessor configured to configure modulation profiles of a communication channel, to select a network element of the plurality of network elements as a test network element, and to send a test signal to the test network element using a configured modulation profile; and

a receiver configured to receive a response to the test signal from the test network element,

wherein the apparatus determines acceptable modulation profiles which can be used to communicate with the network element using responses to the test signal from the test network element.

2. The apparatus of claim 1, wherein the acceptable modulation profiles are determined based on one or more of:

signal to noise ratio, modulation error ratio, packet error rate, burst error rate, forward error correction error rates, network element transmit level, or signal distortion ratio.

3. The apparatus of claim 1, wherein the communication channel is a logical channel which is configured to have a modulation profile matching that of an active channel of a selected network element.

4. The apparatus of claim 3, wherein the receiver is an undedicated receiver in the network.

5. The apparatus of claim 3, wherein the determination of acceptable modulation profiles does not impact existing network communications.

6. A method of identifying a network element to use for testing a network comprising the steps of:

configuring a logical communication channel with a modulation profile matching an active communication channel for a selected network element;

assigning the selected network element to the logical communication channel;

sending a communication to the selected network element via the logical communication channel;

measuring one or more characteristics of a response received from the selected network element; and

determining acceptable modulation profiles which can be used to communicate with the network element based on the one or more characteristics of the response.

7. The method of claim 6, wherein the one or more characteristics include one or more of:

signal to noise ratio, modulation error ratio, packet error rate, burst error rate, forward error correction error rates, network element transmit level, or signal distortion ratio.

8. The method of claim 6, wherein the modulation profile of the channel is increased until it is determined that an unacceptable modulation profile has been reached.

9. The method of claim 8, wherein the modulation profile includes at least one of QPSK, 8QAM, 16QAM, 32QAM, 64QAM, 128QAM, or 256QAM.

10. The method of claim 8, wherein an unacceptable modulation profile is indicated when a non-linearity is detected in the response received from the network element in one or more of the characteristics.

11. A computer readable medium carrying instructions for a computer to perform a method of identifying a network element to use for testing a network comprising the steps of:

configuring a logical communication channel with a modulation profile matching an active communication channel for a selected network element;

assigning the selected network element to the logical communication channel;

sending a communication to the selected network element via the logical communication channel;

measuring one or more characteristics of a response received from the selected network element; and

determining acceptable modulation profiles which can be used to communicate with the network element based on the one or more characteristics of the response.

12. The computer readable medium of claim 11, wherein the one or more characteristics include one or more of:

signal to noise ratio, modulation error ratio, packet error rate, burst error rate, forward error correction error rates, network element transmit level, or signal distortion ratio.

13. The computer readable medium of claim 11, wherein the modulation profile of the channel is increased until it is determined that an unacceptable modulation profile has been reached.

14. The computer readable medium of claim 13, wherein the modulation profile includes at least one of QPSK, 8QAM, 16QAM, 32QAM, 64QAM, 128QAM, or 256QAM.

15. The computer readable medium of claim 13, wherein an unacceptable modulation profile is indicated when a non-linearity is detected in the response received from the network element in one or more of the characteristics.