Systems and methods for loop length and bridged tap length determination of a transmission line

• US 8,687,680 B2
• Filed: 10/04/2013
• Issued: 04/01/2014
• Est. Priority Date: 01/07/2000
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Aware Incorporated (Crowley Holdings Preferred LLC)
• Inventors: Belge, Murat
• Primary Examiner(s): Ahn, Sam K
• Assistant Examiner(s): Perez, James M
• Application Number:
  US14/046,723
• Publication Number:
  US 20140036979A1
• Time in Patent Office: 179 Days
• Field of Search: 375/219, 375/222, 375/224, 375/259, 375/260, 375/295, 375/316, 375/346, 375/354, 375/358, 375/377, 379/1.01, 379/1.03, 379/1.04, 379 22- 24, 379/27.01, 379/27.03, 379/28, 379 2901- 2902, 379/29.09
• US Class Current: 375/222
• CPC Class Codes: H04B 3/46 Monitoring; Testing
• CPC Class Codes: H04B 3/493 Testing echo effects or singing
• CPC Class Codes: H04L 1/004 by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00
• CPC Class Codes: H04L 1/24 Testing correct operation
• CPC Class Codes: H04L 1/245 by using the properties of transmission codes
• CPC Class Codes: H04L 25/0202 Channel estimation
• CPC Class Codes: H04L 25/0216 with estimation of channel length
• CPC Class Codes: H04L 43/50 Testing arrangements
• CPC Class Codes: H04L 5/1438 Negotiation of transmission parameters prior to communication modified according to link quality H04L1/0001
• CPC Class Codes: H04M 3/085 Fault locating arrangements
• CPC Class Codes: H04M 3/2209 for lines also used for data transmission
• CPC Class Codes: H04M 3/2227 Quality of service monitoring
• CPC Class Codes: H04M 3/306 for frequencies above the voice frequency, e.g. xDSL line qualification test methods, test equipment and test arrangements for subscriber lines using xDSL modems H04M3/304; systems modifying transmission characteristics according to link quality H04L1/0001; monitoring and/or testing of line transmission systems H04B3/46

Abstract

Through the use of a least squares minimization concept, the loop length, the number of bridged taps and length of the bridged taps on a transmission line can be determined from readily available modem data. In particular, the loop length, the number of bridge taps and the length of bridged taps can be estimated by comparing a measured frequency domain channel impulse response of the transmission line to a model of a loop that is comprised of multiple sections and multiple bridge taps.

Claims

1. A loop length and bridged tap length estimation system comprising:

a controller and memory that determine a channel transfer function, using one or more signals from an initialization, for a transmission line, the initialization occurring between a first multicarrier transceiver and a second multicarrier transceiver, the one or more signals from the initialization having been transmitted or received using a multiplicity of discrete frequency carriers;

a modeling device that determines a theoretical channel transfer function; and

a loop length and bridged tap determination device that determines a loop length and at least one bridged tap length based on a comparison of the channel transfer function and the theoretical channel transfer function, wherein the theoretical channel transfer function has, as an input, at least one parameter related to a wire gauge of the transmission line.

2. The system of claim 1, wherein the comparison is based on an error minimization function.

3. The system of claim 2, where the error minimization function is a least squares minimization.

4. The system of claim 1, further comprising an impedance determination device that determines at least one of a transmit impedance of a CPE (Customer-Premise Equipment) modem and a receive impedance of a CO (Central Office) modem.

5. The system of claim 1, further comprising a modem identification determining device that determines at least one of an identification of a CPE (Customer-Premise Equipment) modem and an identification of a CO (Central Office) modem.

6. The system of claim 1, wherein the theoretical channel transfer function comprises variables representing a load and a source impedance.

7. The system of claim 1, where the channel transfer function is estimated based on a measured reverb signal.

8. The system of claim 1, wherein the transmission line comprises at least one bridged tap and a wire having said wire gauge.

9. The system of claim 1, wherein the transmission line is used for multicarrier modulation communications.

10. A non-transitory computer-readable information storage media having stored thereon instructions, that when executed, cause to be performed a method for loop length and bridged tap length estimation comprising:

determining a channel transfer function for a transmission line, using one or more signals from an initialization, the initialization occurring between a first multicarrier transceiver and a second multicarrier transceiver, the one or more signals from the initialization having been transmitted or received using a multiplicity of discrete frequency carriers;

determining a theoretical channel transfer function; and

determining a loop length and at least one bridged tap length based on a comparison of the channel transfer function and the theoretical channel transfer function, wherein the theoretical channel transfer function has, as an input, at least one parameter related to a wire gauge of the transmission line.

11. The media of claim 10, wherein the comparison is based on an error minimization function.

12. The media of claim 11, where the error minimization function is a least squares minimization.

13. The media of claim 10, further comprising determining at least one of a transmit impedance of a CPE (Customer-Premise Equipment) modem and a receive impedance of a CO (Central Office) modem.

14. The media of claim 10, further comprising determining at least one of an identification of a CPE (Customer-Premise Equipment) modem and an identification of a CO (Central Office) modem.

15. The media of claim 10, wherein the theoretical channel transfer function comprises variables representing a load and a source impedance.

16. The media of claim 10, where the channel transfer function is estimated based on a measured reverb signal.

17. The media of claim 10, wherein the transmission line comprises at least one bridged tap and a wire having said wire gauge.

18. The media of claim 10, wherein the transmission line is used for multicarrier modulation communications.