INDUCING RESPONSE SIGNATURES IN A COMMUNICATION NETWORK

• US 20110243214A1
• Filed: 06/08/2011
• Published: 10/06/2011
• Est. Priority Date: 02/05/2010
• Status: Active Grant

• Current Assignee: Comcast Cable Communications LLC (Comcast Corporation)
• Original Assignee: Comcast Cable Communications LLC (Comcast Corporation)
• Inventors: Johnston, Bryan Scott, Chang, Phillip F., Wolcott, Lawrence D.
• Granted Patent: US 8,971,394 B2
• Time in Patent Office: Days
• US Class Current: 375/232
• CPC Class Codes: H04L 2025/03471 Tapped delay lines H04L2025/03464 takes precedence
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/03019 adaptive, i.e. capable of adjustment during data reception
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies

Abstract

Methods and systems are provided in which a network induces different distortions in signals traversing different segments of the network. The distortions may be used to identify locations on the network of devices that transmit and receive the signals. The distortions may be reflected in equalization coefficients programmed into transmitting or receiving devices, which may be used to pre or post filter the signals to compensate for the distortions.

Claims

1. A method comprising:

inducing distortions on one or more communication signals traversing multiple segments of a network, wherein a unique signal distortion is induced for each of the multiple segments;

detecting the distortions on the one or more communication signals; and

determining on which of the multiple segments each of the one or more communication signals traversed based on the detected distortions.

2. The method of claim 1, further comprising:

locating a connection point on the network of a first transceiver based on the determined multiple segments traversed by at least one of the communication signals, which was exchanged between the first transceiver and a second transceiver.

3. The method of claim 2:

wherein the first transceiver couples one of multiple devices to the network and the second transceiver couples a communication hub to the network;

wherein the one or more communication signals are exchanged over the network between the multiple devices and the communication hub; and

wherein the method further comprises identifying each of the multiple devices based on data within the one or more communication signals.

4. The method of claim 3, wherein the locating of the connection point on the network of the first transceiver further comprises:

determining which of the multiple devices have previously known connections points on the network;

correlating induced distortions on those communication signals exchanged between the communication hub and the devices having the previously known connection points to induced distortions on the at least one communication signal exchanged between the communication hub and the one device coupled to the first transceiver.

5. The method of claim 1, wherein the one or more communication signals are exchanged over the network between multiple devices and a communication hub, and wherein the method further comprises:

generating, for each of the multiple devices, an associated signature based on the detected distortions;

matching the signature of at least one device to one of multiple predicted signatures, wherein each predicted signature is based on different combinations of one or more of the induced signal distortions; and

identifying which of the multiple segments the at least one devices is connected to based on the matching.

6. The method of claim 5, wherein the signatures are generated based on adaptive equalization coefficients specific to communication signals exchanged between each device and the communication hub.

7. The method of claim 6, further comprising:

calculating, as the signature for each device, a Fourier transform using the adaptive equalization coefficients specific to that device; and

calculating a signature approximation of the signature of each device based on geometric shapes mapped to portions of that device'"'"'s Fourier transform, wherein the matching is based on comparing the signature approximation of the at least one device with signature approximations of the multiple predicted signatures.

8. A system comprising:

a network comprising multiple segments configured to convey communication signals between two points along the network; and

electrical circuits configured to induce distortions in the communication signals traversing the network such that the distortions uniquely identify which of the multiple segments the communication signals have traversed.

9. The system of claim 8, wherein the network comprises a hybrid fiber coaxial network.

10. The system of claim 8, wherein the distortions decrease a signal-to-noise ratio of the communication signals.

11. The system of claim 8, further comprising:

a signal termination hub electrically coupled to the network; and

multiple taps configured to electrically couple multiple devices to the network, wherein the network receives the communication signals at the multiple taps from the devices and conveys the communication signals to the signal termination hub;

12. The system of claim 11, wherein the signal termination hub is configured to detect the signal distortions, and transmit pre-equalization coefficients to the devices for pre-filtering the communication signals to compensate for the distortions.

13. The system of claim 11, further comprising the multiple devices, wherein the multiple devices are configured to pre-filter the communication signals to compensate for the distortions.

14. The system of claim 11, further comprising a server including a processor and memory storing computer executable instructions, that when executed by the processor, cause the server to:

receive pre-equalization coefficients of one or more of the multiple devices from the network; and

uniquely identify which of the multiple segments the communication signals have traversed based on the received pre-equalization coefficients, which are indicative of the induced signal distortions.

15. A method comprising:

inducing a signal distortion on a particular path of multiple paths of a network;

receiving baseline values and subsequent values of adaptive equalization parameters of a device connected to the network, wherein the baseline values were adapted to the network before the inducing of the signal distortion and the subsequent values were adapted to the network during the inducing of the signal distortion; and

determining that the device exchanges communication signals over the particular path on which the signal distortion is induced based on changes between the baseline and subsequent values.

16. The method of claim 15, further comprising:

determining a location of the device based on a stored location of the particular path on which the signal distortion is induced.

17. The method of claim 15, wherein the device is not authorized to access the network.

18. The method of claim 15, wherein the network comprises a hybrid-fiber-coaxial network.

19. The method of claim 15, wherein the signal distortion is induced by connecting a band stop filter to the particular path.

20. The method of claim 15, wherein the induced signal distortion does not interrupt communications of the device over the network.

21. The method of claim 15, further comprising:

receiving communication signals from the device at a termination hub;

measuring the effect of the induced signal distortion on the received communication signals; and

calculating the baseline and subsequent adaptive equalization parameters of the device.

22. The method of claim 15, wherein the baseline and subsequent values of the adaptive equalization parameters are received remotely from a server, which periodically queries the network for the baseline and subsequent values.

23. The method of claim 15, wherein the adaptive equalization parameters are coefficients of a pre-equalization filter in the device.

24. The method of claim 15, further comprising:

calculating time domain to frequency domain transforms of the baseline and subsequent values, wherein the changes between the baseline and subsequent values are determined by comparing the calculated transforms.