System and method to test network performance with impairments

• US 20040073937A1
• Filed: 09/30/2002
• Published: 04/15/2004
• Est. Priority Date: 09/30/2002
• Status: Active Grant

• Current Assignee: Cable Television Laboratories Incorporated
• Original Assignee: Cable Television Laboratories Incorporated
• Inventors: Williams, Thomas H.
• Granted Patent: US 7,451,472 B2
• Time in Patent Office: Days
• US Class Current: 725/107
• CPC Class Codes: H04N 17/00 Diagnosis, testing or measuring for television systems or their details

Abstract

The upstream performance characteristics of a network are measured by looping a signal through both the downstream and upstream paths of the network. Test equipment may be located at a headend of the network and configured to transmit a signal downstream to a remotely located loopback device that redirects the signal in the upstream path to the test equipment. The upstream characteristics may be predominant in the analysis of the return signal because the downstream path may be relatively free from noise.

Claims

1. A method for testing a non-symmetrical network comprising:

providing said network having a first direction of transmission and a second direction of transmission wherein said second direction of transmission has larger impairments than said first direction of transmission and having a distribution point with a downstream connection and an upstream connection;

connecting a loopback device to said network at a remote location, said loopback device adapted to receive a signal from said first direction of transmission, transform said signal, and transmit said signal in said second direction of transmission;

connecting a test apparatus to said network at a distribution point of said network such that the test apparatus input is connected to said upstream connection of said distribution point and the test apparatus output is directed along the downstream path of said network;

creating a signal in said test apparatus transmitting said signal from said test apparatus to said loopback device;

transforming said signal with said loopback device;

transmitting said signal from said loopback device to said distribution point;

transmitting said signal from said distribution point to said test apparatus;

receiving said signal; and

performing at least one measurement of said signal.

2. The method of claim 1 wherein said network comprises a cable television distribution network.

3. The method of claim 2 wherein said test apparatus comprises a cable modem and an upconverter.

4. The method of claim 3 wherein said test apparatus comprises a plurality of cable modems.

5. A method for testing a cable television distribution network comprising:

providing said cable television distribution network having a downstream direction of transmission and an upstream direction of transmission wherein said upstream direction of transmission has larger impairments than said downstream direction of transmission and having a distribution point with a downstream connection and an upstream connection;

connecting a loopback device to said network at a remote location, said loopback device adapted to receive a signal from said first direction of transmission, transform said signal, and transmit said signal in said second direction of transmission;

connecting a test apparatus to said network at a distribution point of said network such that the test apparatus input is connected to said upstream connection of said distribution point and the test apparatus output is directed along the downstream path of said network;

creating a signal in said test apparatus;

transmitting said signal from said test apparatus to said loopback device;

transforming said signal with said loopback device;

transmitting said signal from said loopback device to said distribution point;

transmitting said signal from said distribution point to said test apparatus; and

performing at least one measurement of said signal.

6. The method of claim 5 wherein said test apparatus comprises at least one cable modem.

7. The method of claim 5 wherein said test apparatus comprises a telephony device.

8. A cable television distribution network with a testing capability comprising:

a loopback device connected to said network at a remote location, said loopback device adapted to receive a signal from the downstream direction of said network, transform said signal, and transmit said signal in the upstream direction of said network;

a test apparatus connected to said network at a distribution point of said network such that the test apparatus input is connected to said upstream connection of said distribution point and the test apparatus output is directed along the downstream path of said network, said test apparatus adapted to create a signal in said test apparatus, transmit said signal from said test apparatus to said loopback device wherein said signal is transformed by said loopback device and transmitted from said loopback device to said distribution point wherefrom said signal is transmitted to said test apparatus and measured.

9. The cable television network of claim 8 wherein said test apparatus comprises a cable modem.

10. The cable television network of claim 8 wherein said test apparatus comprises a telephony device.

11. A cable television distribution network with a testing capability comprising:

at least one loopback means connected to said network at a remote location, said loopback means adapted to receive a signal from the downstream direction of said network, transform said signal, and transmit said signal in the upstream direction of said network; and

a testing means connected to said network at a distribution point of said network such that the input of said testing means is connected to said upstream connection of said distribution point and the output of said testing means is directed along the downstream path of said network, wherein said testing means comprises a cable modem.

12. The cable television distribution network of claim 11 wherein said loopback means is further adapted to be remotely activated and deactivated.