Determining Response Signature Commonalities

• US 20110197071A1
• Filed: 11/01/2010
• Published: 08/11/2011
• 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: Chang, Phillip F., Wolcott, Lawrence D.
• Granted Patent: US 8,856,535 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: H04L 2025/0342 QAM
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/022 of frequency response
• CPC Class Codes: H04L 25/03 Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
• CPC Class Codes: H04L 25/03019 adaptive, i.e. capable of adjustment during data reception
• CPC Class Codes: H04L 43/0823 Errors, e.g. transmission errors
• CPC Class Codes: H04L 63/107 wherein the security policies are location-dependent, e.g. entities privileges depend on current location or allowing specific operations only from locally connected terminals
• CPC Class Codes: H04L 67/52 specially adapted for the location of the user terminal

Abstract

An analyzer can obtain data regarding signal characteristics in each of multiple communication channels within an access network. The analyzer can use that data to create signatures corresponding to each of the multiple channels. Based on similarities between signatures, the analyzer may then identify clusters of signatures associated with devices that share channels or portions of channels.

Claims

1. A method comprising:

generating, using one or more processors and for each of multiple access devices in communication with a hub device in a network, at least one associated frequency response signature based on communications between that access device and the hub device;

calculating a signature approximation for each of the frequency response signatures;

associating each frequency response signature with one of multiple signature clusters, wherein each frequency response signature is associated with one of the clusters based on similarities between the signature approximation of the frequency response signature and signature approximations of other frequency response signatures associated with that cluster; and

identifying at least one of the access devices based on identification of one of the signature clusters associated with the at least one access device.

2. The method of claim 1, wherein the network comprises a hybrid fiber coaxial network.

3. The method of claim 1, wherein the generating comprises, for each of the multiple access devices, performing a Fourier transform using adaptive equalization coefficients specific to communications between that access device and the hub device, and wherein for each frequency response signature the signature approximation is derived from geometric shapes mapped to portions of the response signature.

4. The method of claim 1, wherein the calculating comprises, for each of the frequency response signatures, deriving a signature approximation from triangles mapped to portions of the frequency response signature.

5. The method of claim 4, wherein each of the signature approximations includes a first value representing a number of mapped triangles used to derive the signature approximation and a plurality of additional values representing areas of those mapped triangles.

6. The method of claim 4, wherein each of the signature approximations includes a value representing a sum of areas of mapped triangles used to derive the signature approximation.

7. The method of claim 1, wherein the identifying comprises identifying one or more authorized access devices having known locations based on identification of a signature cluster associated with an unauthorized access device having an unknown location.

8. The method of claim 1, wherein the at least one associated frequency response signature comprises, for each of the multiple access devices, an amplitude/frequency response signature, a group delay/frequency response signature and a phase delay/frequency response signature.

9. The method of claim 8, wherein the identifying comprises identifying access devices associated with an amplitude/frequency response signature having a first set of criteria, associated with a group delay/frequency response signature having a second set of criteria different from the first set of criteria, and associated with a phase delay/frequency response signature having a third set of criteria different from the first set of criteria.

10. A tangible machine-readable storage medium storing machine-executable instructions for performing a method comprising:

generating, using one or more processors and for each of multiple access devices in communication with a hub device in a network, at least one associated frequency response signature based on communications between that access device and the hub device;

calculating a signature approximation for each of the frequency response signatures;

associating each frequency response signature with one of multiple signature clusters, wherein each frequency response signature is associated with one of the clusters based on similarities between the signature approximation of the frequency response signature and signature approximations of other frequency response signatures associated with that cluster; and

identifying at least one of the access devices based on identification of one of the signature clusters associated with the at least one access device.

11. The tangible machine-readable storage medium of claim 10, wherein the network comprises a hybrid fiber coaxial network.

12. The tangible machine-readable storage medium of claim 10, wherein the generating comprises, for each of the multiple access devices, performing a Fourier transform using adaptive equalization coefficients specific to communications between that access device and the hub device, and wherein for each frequency response signature the signature approximation is derived from geometric shapes mapped to portions of the response signature.

13. The tangible machine-readable storage medium of claim 10, wherein the calculating comprises, for each of the frequency response signatures, deriving a signature approximation from triangles mapped to portions of the frequency response signature.

14. The tangible machine-readable storage medium of claim 13, wherein each of the signature approximations includes a first value representing a number of mapped triangles used to derive the signature approximation and a plurality of additional values representing areas of those mapped triangles.

15. The tangible machine-readable storage medium of claim 13, wherein each of the signature approximations includes a value representing a sum of areas of mapped triangles used to derive the signature approximation.

16. The tangible machine-readable storage medium of claim 10, wherein the identifying comprises identifying one or more authorized access devices having known locations based on identification of a signature cluster associated with an unauthorized access device having an unknown location.

17. The tangible machine-readable storage medium of claim 10, wherein the at least one associated frequency response signature comprises, for each of the multiple access devices, an amplitude/frequency response signature, a group delay/frequency response signature and a phase delay/frequency response signature.

18. The tangible machine-readable storage medium of claim 17, wherein the identifying comprises identifying access devices associated with an amplitude/frequency response signature having a first set of criteria, associated with a group delay/frequency response signature having a second set of criteria different from the first set of criteria, and associated with a phase delay/frequency response signature having a third set of criteria different from the first set of criteria.

19. An apparatus comprising:

at least one processor; and

at least one memory having stored therein machine executable instructions, the at least one memory and the instructions stored thereon configured, with the at least one processor, to cause the apparatus to

generate, for each of multiple access devices in communication with a hub device in a network, at least one associated frequency response signature based on communications between that access device and the hub device,

calculate a signature approximation for each of the frequency response signatures,

associate each frequency response signature with one of multiple signature clusters, wherein each frequency response signature is associated with one of the clusters based on similarities between the signature approximation of the frequency response signature and signature approximations of other frequency response signatures associated with that cluster, and

identify at least one of the access devices based on identification of one of the signature clusters associated with the at least one access device.

20. The apparatus of claim 19, wherein the apparatus is part of a system that includes the multiple access devices and the hub device.