LEAKAGE DETECTION IN AN ALL-DIGITAL CABLE DISTRIBUTION NETWORK

• US 20140105251A1
• Filed: 10/16/2013
• Published: 04/17/2014
• Est. Priority Date: 10/16/2012
• Status: Abandoned Application

• Current Assignee: Effigis Geo Solutions
• Original Assignee: Effigis Geo Solutions
• Inventors: Bouchard, Magella
• Application Number:
  US14/055,515
• Publication Number:
  US 20140105251A1
• Time in Patent Office: Days
• US Class Current: 375/141
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 3/46 Monitoring; Testing

Abstract

The present document describes a method for detecting a leak in an all-digital cable distribution network comprising a head station for transmitting content to subscribers using channels that are encoded using quadrature amplitude modulation (QAM), the method comprising: injecting at the head station, through the cable distribution network and using a direct sequence spread spectrum (DSSS) transmitter, a DSSS signal of a frequency range not overlapping with an adjacent QAM channel; travelling the area where the cable distribution network is deployed, with a DSSS receiver tuned to the DSSS transmitter at the head station; and upon detecting, at the DSSS receiver, a DSSS signal leaking through the leak of the cable distribution network, determining the location of leak for repair, or generating a leakage event data package that may be transmitted or stored.

Claims

1. A method for detecting a leak in an all-digital cable distribution network deployed in an area and comprising a head station for transmitting content to subscribers using channels that are encoded using quadrature amplitude modulation (QAM), the method comprising:

injecting at the head station, through the all-digital cable distribution network and using a direct sequence spread spectrum (DSSS) transmitter, a DSSS signal of a frequency range not overlapping with an adjacent QAM channel;

travelling the area where the all-digital cable distribution network is deployed, with a DSSS receiver tuned to the DSSS transmitter at the head station;

upon detecting, at the DSSS receiver, a DSSS signal leaking through the leak of the cable distribution network, collecting data indicative of a strength of the DSSS signal and associating the collected data with a location at which the DSSS signal was detected for generating leakage event data; and

at least one of transmitting and storing the leakage event data for processing.

2. The method of claim 1, wherein detecting the DSSS signal at the DSSS receiver comprises de-spreading the signal for retrieving an original modulated signal.

3. The method of claim 1, wherein generating a leakage event data comprises processing the leakage event data to eliminate multiple appearances of a leak.

4. The method of claim 3, wherein generating a leakage event data further comprises generating a map indicating the leak.

5. The method of claim 4, wherein generating a map indicating leak events comprises using specific symbols to indicate at least one of a type of event and a signal strength, the specific symbols comprising at least one of a specific shape and a specific color.

6. The method of claim 1, further comprising dispatching repairs to a work force management system via a data interface.

7. A method for detecting a leak in an all-digital cable distribution network deployed in an area and comprising a head station for transmitting content to subscribers using channels that are encoded using quadrature amplitude modulation (QAM), the method comprising:

injecting at the head station, through the all-digital cable distribution network and using a direct sequence spread spectrum (DSSS) transmitter, a DSSS signal of a frequency range not overlapping with an adjacent QAM channel;

travelling the area where the all-digital cable distribution network is deployed, with a DSSS receiver tuned to the DSSS transmitter at the head station;

upon detecting, at the DSSS receiver, a DSSS signal leaking through the leak of the all-digital cable distribution network, determining a location of a leak for repair.

8. The method of claim 7, wherein detecting the DSSS signal comprises collecting data indicative of a strength of the DSSS signal for determining the location of a leak.

9. The method of claim 7, wherein detecting the DSSS signal at the DSSS receiver comprises de-spreading the signal for retrieving an original modulated signal.

10. A system for detecting a leak in an all-digital cable distribution network deployed in an area, the system comprising:

a head station for transmitting content to subscribers using channels that are encoded using quadrature amplitude modulation (QAM);

a direct sequence spread spectrum (DSSS) transmitter for injecting at the head station, through the all-digital cable distribution network, a DSSS signal of a frequency range not overlapping with an adjacent QAM channel; and

a DSSS receiver tuned to the DSSS transmitter at the head station for detecting a DSSS signal leaking through the leak of the all-digital cable distribution network.

11. The system of claim 10, further comprising a processor configured for determining a location of a leak for repair.

12. The system of claim 10, wherein the DSSS receiver is installed on a vehicle for travelling the area where the all-digital cable distribution network is deployed.

13. The system of claim 12, wherein the vehicle comprises a geo-locating device installed thereon for determining the location at which the DSSS signal was detected.

14. The system of claim 10, wherein the DSSS receiver comprises a handheld portable receiver.

15. The system of claim 10, wherein the DSSS transmitter for injecting the DSSS signal comprises a DSSS transmitter for injecting the DSSS signal of a bandwidth comprised between 400 kHz and 600 kHz.

16. The system of claim 10, wherein the DSSS receiver comprises a FPGA configured for frequency tuning the DSSS receiver to the DSSS transmitter.