Inducing response signatures in a communication network

• US 9,537,680 B2
• Filed: 01/07/2015
• Issued: 01/03/2017
• 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: Wolcott, Lawrence D., Chang, Phillip F., Johnston, Bryan Scott
• Primary Examiner(s): Mehedi, Morshed
• Assistant Examiner(s): Alata, Ayoub
• Application Number:
  US14/591,429
• Publication Number:
  US 20150256430A1
• Time in Patent Office: 727 Days
• US Class Current: 1/1
• 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:

introducing a plurality of different distortions at a plurality of segments of a network, wherein a segment of the plurality of segments is a wireless segment and a different segment of the plurality of segments is a fiber optic medium segment;

determining, by a computing device, an approximation of an amplitude versus frequency response derived from a communication signal that traversed at least one segment of the plurality of segments; and

comparing the approximation with one or more predicted responses to determine that the communication signal traversed at least one of the wireless segment and the fiber optic medium segment.

2. The method of claim 1, further comprising:

approximating a location of a device on the network not authorized to access the network based on a location of at least one of the wireless segment and the fiber optic medium segment.

3. The method of claim 1, wherein at least one predicted response, of the one or more predicted responses, is based on a distortion, of the plurality of different distortions, introduced at the wireless segment.

4. The method of claim 1, wherein at least one predicted response, of the one or more predicted responses, is based on a distortion, of the plurality of different distortions, introduced at the fiber optic medium segment.

5. The method of claim 1, further comprising:

determining a plurality of vector sign changes of the amplitude versus frequency response to determine the approximation.

6. The method of claim 1, wherein the communication signal is exchanged between a device and a communication hub, wherein the amplitude versus frequency response is a Fourier transform generated based on adaptive equalization coefficients specific to the communication signal exchanged between the device and the communication hub.

7. The method of claim 6, further comprising:

mapping a geometric shape to at least a portion of the Fourier transform to produce the approximation.

8. The method of claim 1, wherein at least one of the plurality of different distortions results in a notch in the communication signal at a particular center frequency.

9. A method comprising:

introducing a plurality of different distortions at a plurality of segments of a network, wherein a segment of the plurality of segments is a wireless segment and a different segment of the plurality of segments is a fiber optic medium segment;

determining, by a computing device, an amplitude versus frequency response of a communication signal that traversed at least one of the wireless segment and the fiber optic medium segment;

determining an approximation based on the amplitude versus frequency response; and

determining, by the computing device, at least one of the wireless segment and the fiber optic medium segment as being traversed by the communication signal based on a comparison of the approximation associated with the communication signal with a plurality of predicted responses associated with the plurality of different distortions.

10. The method of claim 9, wherein a distortion, of the plurality of different distortions, is introduced by a band stop filter and decreases a signal-to-noise ratio of the communication signal.

11. The method of claim 9, wherein at least one predicted response, of the plurality of predicted responses, is based on a distortion, of the plurality of different distortions, introduced at the wireless segment.

12. The method of claim 9, wherein at least one predicted response, of the plurality of predicted responses, is based on a distortion, of the plurality of different distortions, introduced at the fiber optic medium segment.

13. The method of claim 9, further comprising:

approximating a location of a device on the network and not authorized to access the network based on a location of at least one of the wireless segment and the fiber optic medium segment.

20. The method of claim 9, wherein at least one of the plurality of different distortions results in a notch in the communication signal at a particular center frequency.

14. A method comprising:

introducing a distortion at a wireless segment of a network and a different distortion at a fiber optic medium segment of the network;

determining, by a computing device, an amplitude versus frequency response of a communication signal that traversed at least one segment of the network;

determining an approximation based on the amplitude versus frequency response; and

identifying at least one of the wireless segment and the fiber optic medium segment as being traversed by the communication signal based on a comparison of the approximation with a predicted response associated with the distortion introduced at the wireless segment and a predicted response associated with the different distortion introduced at the fiber optic medium segment.

15. The method of claim 14, further comprising:

approximating a location of a device on the network not authorized to access the network based on a location of the at least one of the wireless segment and the fiber optic medium segment.

16. The method of claim 14, further comprising:

determining a plurality of vector sign changes of the amplitude versus frequency response to determine the approximation.

17. The method of claim 14, wherein the distortion at the wireless segment results in a notch in the communication signal at a particular center frequency.

18. The method of claim 14, wherein the amplitude versus frequency response is a Fourier transform generated based on adaptive equalization coefficients specific to the communication signal exchanged between a device and a communication hub.

19. The method of claim 18, further comprising:

mapping a geometric shape to at least a portion of the Fourier transform to produce the approximation.