Asymmetric digital subscriber line methods suitable for long subscriber loops

• US 20020001340A1
• Filed: 03/28/2001
• Published: 01/03/2002
• Est. Priority Date: 03/29/2000
• Status: Active Grant

• Current Assignee: Microsemi Frequency And Time Corporation
• Original Assignee: Symmetricom Incorporated (Microchip Technology Incorporated)
• Inventors: Shenoi, Kishan, Bogardus, Gary, Squadrito, Sandro
• Granted Patent: US 6,507,606 B2
• Time in Patent Office: Days
• US Class Current: 375/211
• CPC Class Codes: H04L 25/22 Repeaters for converting two wires to four wires; Repeaters for converting single current to double current
• CPC Class Codes: H04L 27/26416 Filtering per subcarrier, e.g. filterbank multicarrier [FBMC]
• CPC Class Codes: H04L 27/2653 with direct demodulation of individual subcarriers
• CPC Class Codes: H04L 27/2654 Filtering per subcarrier, e.g. filterbank multicarrier [FBMC]
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence

Abstract

Systems and methods are described for asymmetric digital subscriber loops. A method includes utilizing a circuit having a first end and a second end, the circuit having a first amplification interface connecting the first end to the second end in a first direction, and a second amplification interface connecting the second end to the first end in a second direction; adapting the first amplification interface to provide a first gain adjustment as a function of a first attenuation of a first communication by a first direction impedance from the transmission medium while transmitting in the first direction, the first communication within a first frequency range over the transmission medium from the first end to the second end; and adapting the second amplification interface to provide a second gain adjustment as a function of a second attenuation of a second communication by a second direction impedance from the transmission medium while transmitting in the second direction, the second communication within a second frequency range over the transmission medium from the second end to said first end. An apparatus includes a modulator for transmitting a first communication, in a first direction over a transmission medium, the modulator operably coupled to a first amplification interface for providing a first gain adjustment, based on a first attenuation of the first communication in the first direction by a first direction impedance of the transmission medium; and a demodulator operably coupled to the modulator, for receiving a second communication, in a second direction over the transmission medium, the demodulator operably coupled to a second amplification interface for providing a second gain adjustment, based on a second attenuation of the second communication in the second direction by a second direction impedance of the transmission medium.

Claims

1. A method, comprising:

utilizing a circuit having a first end and a second end, said circuit having a first amplification interface connecting said first end to said second end in a first direction, and a second amplification interface connecting said second end to said first end in a second direction;

adapting said first amplification interface to provide a first gain adjustment as a function of a first attenuation of a first communication by a first direction impedance from said transmission medium while transmitting in said first direction, said first communication within a first frequency range over said transmission medium from said first end to said second end; and

adapting said second amplification interface to provide a second gain adjustment as a function of a second attenuation of a second communication by a second direction impedance from said transmission medium while transmitting in said second direction, said second communication within a second frequency range over said transmission medium from said second end to said first end.

2. The method of claim 1, wherein utilizing said circuit includes I) utilizing a repeater circuit and II) removing from said transmission medium a load coil pair interposed between said first end and said second end.

3. The method of claim 1, wherein utilizing said circuit includes utilizing a repeater circuit and coupling said repeater circuit to said transmission medium in a parallel relationship with a load coil pair interposed between said first end and said second end.

4. A computer program, comprising computer or machine readable program elements translatable for implementing the method of claim 1.

5. An apparatus for performing the method of claim 1.

6. An electronic media, comprising a program for performing the method of claim 1.

7. An apparatus, comprising the electronic media of claim 6.

8. A process, comprising utilizing the apparatus of claim 7.

9. A method for modulation and demodulation on a discrete multi-tone asymmetric digital subscriber loop, comprising:

adapting a first asymmetric digital subscriber loop data pump to operate in a downstream direction using a first weighting network, said first weighting network having a first filter bank including a first plurality of filters, each of said first plurality of filters having a first filter length longer than a first sample size which corresponds to a first discrete Fourier transform size used for the downstream direction;

adapting a second asymmetric digital subscriber loop data pump to operate in an upstream direction using a second weighting network, said second weighting network having a second filter bank including a second plurality of filters, each of said second plurality of filters having a second filter length longer than a second sample size which corresponds to a second discrete Fourier transform size used for the upstream direction;

adapting a first asymmetric digital subscriber loop data receiver to operate in said upstream direction using an equivalent of said second weighting network; and

adapting a second asymmetric digital subscriber loop data receiver to operate in said downstream direction using an equivalent of said first weighting network.

10. The method of claim 9, wherein adapting said asymmetric digital subscriber loop data pump includes, sampling at a line-sampling rate defined by a product of said sample size and a symbol rate at which one or more symbols are generated for transmission, each of the one or more symbols defining a block of said sample size.

11. The method of claim 9, wherein adapting said ADSL data receiver includes, sampling at a line-sampling rate defined by a product of said sample size and a symbol rate at which one or more symbols are generated for transmission, each of the one or more symbols defining a block of said sample size.

12. A computer program, comprising computer or machine readable program elements translatable for implementing the method of claim 9.

13. An apparatus for performing the method of claim 9.

14. An electronic media, comprising a program for performing the method of claim 9.

15. An apparatus, comprising the electronic media of claim 14.

16. A process, comprising utilizing the apparatus of claim 15.

17. A method, comprising:

splitting a transmission medium at an intermediate point between a first end and a second end to deploy a repeater circuit for extending said transmission medium, said repeater circuit having a first amplification interface and a second amplification interface;

coupling said repeater circuit at the intermediate point;

configuring said first amplification interface to provide a first gain adjustment as a function of a first attenuation of a first communication by a first direction impedance from said transmission medium while transmitting said first communication over said transmission medium from said first end to said second end; and

configuring said second amplification interface to provide a second gain adjustment as a function of a second attenuation of a second communication by a second direction impedance from said transmission medium while transmitting said second communication over said transmission medium from said second end to said first end.

18. The method of claim 17, wherein coupling said repeater circuit includes removing from said transmission medium a load coil pair interposed between said first end and said second end.

19. The method of claim 17, wherein coupling said repeater circuit includes connecting said repeater circuit to said transmission medium in a parallel relationship with a load coil pair interposed between said first end and said second end.

20. The method of claim 19, wherein

configuring said first amplification interface includes using a first weighting network, said first weighting network having a first filter bank including a first plurality of filters, each of said first plurality of filters having a filter length longer than a sample size, said first weighting network deployed to pump downstream data in said first direction while providing said first gain adjustment, and

configuring said second amplification interface includes using a second weighting network, said second weighting network having a second filter bank including a second plurality of filters, each of said second plurality of filters having said filter length longer than said sample size, said second weighting network deployed to pump upstream data in said second direction while providing said second gain adjustment.

21. The method of claim 20, wherein configuring said first amplification interface includes, sampling at a line-sampling rate defined by a product of said sample size and a symbol rate at which one or more symbols are generated for transmission, each of the one or more symbols defining a block of said sample size.

22. The method of claim 20, wherein configuring said second amplification interface includes, sampling at a line-sampling rate defined by a product of said sample size and a symbol rate at which one or more symbols are generated for transmission, each of the one or more symbols defining a block of said sample size.

23. A computer program, comprising computer or machine readable program elements translatable for implementing the method of claim 17.

24. An apparatus for performing the method of claim 17.

25. An electronic media, comprising a program for performing the method of claim 17.

26. An apparatus, comprising the electronic media of claim 25.

27. A process, comprising utilizing the apparatus of claim 26.

28. A method for transmitting asymmetric digital subscriber loop communications including a first communication within a first frequency range and a second communication within a second frequency range over a subscriber loop including a first communication line and a second communication line, said first communication line and said second communication line connecting a first loop end to a second loop end, comprising:

splitting the subscriber loop at an intermediate point between said first loop end and said second loop end to provide a first gap in said first communication line and a second gap in said second communication line;

deploying a first load coil in series with said first communication line at the first gap and a second load coil in series with said second communication line at the second gap;

coupling a repeater circuit to said subscriber loop in a parallel relationship across said first load coil and said second load coil, said repeater circuit including a first amplification interface coupled to said first communication line and a second amplification interface coupled to said second communication line;

adjusting said first amplification interface to pump downstream data in a first direction from said first loop end to said second loop end over said first communication line while providing a first gain adjustment, based on a first direction attenuation of said first communication by a first direction impedance of said subscriber loop; and

adjusting said second amplification interface to pump upstream data in a second direction from said second loop end to said first loop end over said second communication line while providing a second gain adjustment, based on a second direction attenuation of said second communication by a second direction impedance of said subscriber loop.

29. The method of claim 28, wherein

adjusting said first amplification interface includes using a first weighting network, said first weighting network having a first filter bank including a first plurality of filters, each of said first plurality of filters having a filter length longer than a sample size, said first weighting network deployed to pump downstream data in said first direction while providing said first gain adjustment, and

adjusting said second amplification interface includes using a second weighting network, said second weighting network having a second filter bank including a second plurality of filters, each of said second plurality of filters having said filter length longer than said sample size, said second weighting network deployed to pump upstream data in said second direction while providing said second gain adjustment.

30. The method of claim 29, wherein configuring said first amplification interface includes, sampling at a line-sampling rate defined by a product of said sample size and a symbol rate at which one or more symbols are generated for transmission, each of the one or more symbols defining a block of said sample size.

31. The method of claim 29, wherein configuring said second amplification interface includes, sampling at a line-sampling rate defined by a product of said sample size and a symbol rate at which one or more symbols are generated for transmission, each of the one or more symbols defining a block of said sample size.

32. A computer program, comprising computer or machine readable program elements translatable for implementing the method of claim 28.

33. An apparatus for performing the method of claim 28.

34. An electronic media, comprising a program for performing the method of claim 28.

35. An apparatus, comprising the electronic media of claim 34.

36. A process, comprising utilizing the apparatus of claim 35.

37. An apparatus, comprising:

a modulator for transmitting a first communication, in a first direction over a transmission medium, said modulator operably coupled to a first amplification interface for providing a first gain adjustment, based on a first attenuation of said first communication in said first direction by a first direction impedance of said transmission medium; and

a demodulator operably coupled to said modulator, for receiving a second communication, in a second direction over said transmission medium, said demodulator operably coupled to a second amplification interface for providing a second gain adjustment, based on a second attenuation of said second communication in said second direction by a second direction impedance of said transmission medium.

38. The apparatus of claim 37, wherein the modulator includes a modulator circuit.

39. The apparatus of claim 37, wherein the demodulator includes a demodulator circuit.

40. The apparatus of claim 37, the first amplification interface including a first filter bank having a first plurality of filters, each of said first plurality of filters having said filter length longer than a sample size to provide said second gain adjustment, and the second amplification interface including a second filter bank having a second plurality of filters, each of said second plurality of filters having said filter length longer than said sample size to provide said second gain adjustment.

41. A method for extending a range of a digital subscriber loop signal which comprises utilizing the apparatus of claim 37.

42. A modem, comprising the apparatus of claim 37.

43. A repeater, comprising the modem of claim 37.

44. A kit, comprising:

the apparatus of claim 37.

45. The kit of claim 44, further comprising instructions.

46. A transceiver, comprising:

a modulation circuit for transmitting a first communication, in a first direction over a transmission medium, said modulation circuit including a first filter bank including a first plurality of filters, each of said first plurality of filters having a filter length longer than a sample size, deployed in said modulation circuit to provide a first gain adjustment, based on a first attenuation of said first communication in said first direction by a first direction impedance of said transmission medium; and

a demodulation circuit coupled to said modulation circuit, for receiving a second communication, in a second direction over said transmission medium, said demodulation circuit including a second filter bank including a second plurality of filters, each of said second plurality of filters having said filter length longer than said sample size, deployed in said demodulation circuit to provide a second gain adjustment, based on a second attenuation of said second communication in said second direction by a second direction impedance of said transmission medium.

47. The transceiver of claim 46, wherein the transceiver includes an asymmetric digital subscriber loop modem.

48. The transceiver of claim 46, wherein the transmission medium includes a subscriber loop interposed between a central office equipment and a customer premise equipment.

49. The transceiver of claim 48, wherein said first communication providing downstream data in said first direction over said subscriber loop.

50. The transceiver of claim 48, wherein said second communication providing upstream data in said second direction over said subscriber loop.

51. The transceiver of claim 48, wherein the modulation circuit includes a channel modulation circuit for transmitting from a data source at said central office equipment to said customer premise equipment said first communication.

52. The transceiver of claim 48, wherein the demodulation circuit includes a channel demodulation circuit for receiving from said customer premise equipment to a data sink at said central office equipment said second communication.

53. A method for extending a range of a digital subscriber loop signal which comprises utilizing the transceiver of claim 46.

54. A modem, comprising the transceiver of claim 46.

55. A repeater, comprising the modem of claim 54.

56. A kit, comprising:

the transceiver of claim 46.

57. The kit of claim 56, further comprising instructions.

58. An asymmetric digital subscriber loop modem, comprising:

a channel modulation circuit for transmitting a first communication in a first direction over an asymmetric digital subscriber loop, said channel modulation circuit including a first weighting network, said first weighting network having a first filter bank including a first plurality of filters, each of said first plurality of filters having a filter length longer than a sample size, deployed to pump data in said first direction while providing a first gain adjustment, based on a first direction attenuation of said first communication by a first direction impedance of said asymmetric digital subscriber loop; and

a channel demodulation circuit coupled to said channel modulation circuit, for receiving a second communication in a second direction over said asymmetric digital subscriber loop, said channel demodulation circuit including a second weighting network, said second weighting network having a second filter bank including a second plurality of filters, each of said second plurality of filters having said filter length longer than said sample size, deployed to pump upstream data in said second direction while providing a second gain adjustment, based on a second direction attenuation of said second communication by a second direction impedance of said asymmetric digital subscriber loop.

59. The asymmetric digital subscriber loop modem of claim 58, wherein said first communication uses a first frequency range and said second communication uses a second frequency range that does not overlap said first frequency range.

60. The asymmetric digital subscriber loop modem of claim 58, wherein said first plurality of filters includes a first set of digital finite impulse response filters, each of said first set of digital finite impulse response filters having a length that is a product of a number of active taps and said sample size.

61. The asymmetric digital subscriber loop modem of claim 60, wherein said second plurality of filters includes a second set of digital finite impulse response filters, each of said second set of digital finite impulse response filters having said length that is the product of said number of active taps and said sample size.

62. The asymmetric digital subscriber loop modem of claim 61, wherein said asymmetric digital subscriber loop modem samples at a line-sampling rate defined by a product of said sample size and a symbol rate at which one or more symbols are generated for transmission, each symbol of said one or more symbols defining a block of said sample size.

63. A method for extending a range of a digital subscriber loop signal which comprises utilizing the asymmetric digital subscriber loop modem of claim 58.

64. A repeater, comprising the asymmetric digital subscriber loop modem of claim 58.

65. A kit, comprising:

the asymmetric digital subscriber loop modem of claim 58.

66. The kit of claim 65, further comprising instructions.

67. A communication system, comprising:

a channel modulation circuit for transmitting from a data source at a central office equipment to a customer premise equipment, a first communication having downstream data in a first direction over a subscriber loop interposed between said central office equipment and said customer premise equipment, said channel modulation circuit including a first weighting network, said first weighting network having a first filter bank including a first plurality of filters, each of said first plurality of filters having a filter length longer than a sample size, deployed to pump downstream data in said first direction while providing a first gain adjustment, based on a first direction attenuation of said first communication by a first direction impedance of said subscriber loop; and

a channel demodulation circuit coupled to said channel modulation circuit, for receiving from said customer premise equipment to a data sink at said central office equipment, a second communication having upstream data in a second direction over said subscriber loop, said channel demodulation circuit including a second weighting network, said second weighting network having a second filter bank including a second plurality of filters, each of said second plurality of filters having said filter length longer than said sample size, deployed to pump upstream data in said second direction while providing a second gain adjustment, based on a second direction attenuation of said second communication by a second direction impedance of said subscriber loop,

wherein said communication system is operably coupled to said subscriber loop, the system providing a simultaneous access to the subscriber loop by a plain old telephone service telephone equipment transmitting voice communications in a first frequency band, and by an asymmetric digital subscriber loop modem transmitting asymmetric digital subscriber loop communications in a second frequency band higher than the first frequency band.