SYSTEMS AND METHODS FOR INTEGRATING ASYNCHRONOUS SIGNALS IN DISTRIBUTED ANTENNA SYSTEM WITH DIRECT DIGITAL INTERFACE TO BASE STATION

• US 20150098372A1
• Filed: 10/03/2014
• Published: 04/09/2015
• Est. Priority Date: 10/07/2013
• Status: Active Grant

• Current Assignee: Commscope Emea Limited (CommScope Holding Company, Inc.), CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Zavadsky, Dean, Wala, Philip M.
• Granted Patent: US 9,787,457 B2
• Time in Patent Office: Days
• US Class Current: 370/281
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence
• CPC Class Codes: H04L 5/1469 using time-sharing
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

A signal interface unit in a radio system includes an external device interface configured to receive a downlink asynchronous radio carrier signal for a radio frequency carrier from an external device; a clock conversion unit communicatively coupled to the external device interface and configured to re-clock the downlink asynchronous radio carrier signal to a master clock of the radio system from the clock of the external device; and an antenna side interface configured to communicate at least one of the re-clocked downlink asynchronous radio carrier signal and a downlink digitized radio frequency signal based on the re-clocked downlink asynchronous radio carrier signal to an antenna unit.

Claims

1. A signal interface unit in a radio system, comprising:

an external device interface configured to receive a downlink asynchronous radio carrier signal for a radio frequency carrier from an external device;

a clock conversion unit communicatively coupled to the external device interface and configured to re-clock the downlink asynchronous radio carrier signal to a master clock of the radio system from the clock of the external device; and

an antenna side interface configured to communicate at least one of the re-clocked downlink asynchronous radio carrier signal and a downlink digitized radio frequency signal based on the re-clocked downlink asynchronous radio carrier signal to an antenna unit.

2. The signal interface unit of claim 1, wherein the clock conversion unit includes a resampling filter that re-clocks the downlink asynchronous radio carrier signal to the master clock of the radio system from the clock of the external device.

3. The signal interface unit of claim 1, wherein the clock conversion unit converts from a first clock domain of the external device to a second clock domain of the radio system using a Farrow structure.

4. The signal interface unit of claim 1, wherein the clock conversion unit is configured to re-clock the downlink asynchronous radio carrier signal by converting first samples of a channelized radio carrier synchronous with a first clock of a first clock domain to second samples synchronous with a second clock of a second clock domain.

5. The signal interface unit of claim 1, wherein the downlink asynchronous radio carrier signal is specific to a particular channel and requires additional baseband conversion before radio frequency conversion and transmission can be performed;

and

wherein the downlink digitized radio frequency signal is not specific to a particular channel and does not require additional baseband conversion before radio frequency conversion and transmission can be performed.

6. The signal interface unit of claim 1, wherein the downlink asynchronous radio carrier signal includes I/Q pairs.

7. The signal interface unit of claim 1, further comprising:

a signal conversion module communicatively coupled between the external device interface and the antenna side interface and configured to generate the downlink digitized radio frequency signal based on the re-clocked downlink asynchronous radio carrier signal.

8. The signal interface unit of claim 1, wherein the antenna unit is a remote antenna unit communicatively coupled to the signal interface unit by at least one medium.

9. The signal interface unit of claim 8, wherein the distributed antenna system network interface is configured to communicate the downlink digital radio frequency signal directly to the remote antenna unit across the at least one medium.

10. The signal interface unit of claim 8, wherein the signal interface is communicatively coupled with an intermediary device that aggregates the downlink digital radio frequency signal with at least one other downlink digital radio frequency signal before being transmitted to the remote antenna unit.

11. The signal interface unit of claim 10, wherein individual channels within the downlink digital radio frequency signal and the at least one other downlink digital radio frequency signal do not overlap and can be upconverted together simultaneously to radio frequency spectrum.

12. The signal interface unit of claim 8, wherein the at least one medium includes at least one of a wired medium and a wireless medium.

13. The signal interface unit of claim 8, wherein the signal interface communicates at least one of digital signals and analog signals to the remote antenna unit across the at least one medium.

14. The signal interface unit of claim 1, wherein the external device is part of a base band unit of a base station.

15. The signal interface unit of claim 1, wherein the external device is at least one of a Common Public Radio Interface (CPRI) base station interface, an Open Base Station Architecture Initiative (OBSAI) base station interface, and an Open Radio Interface (ORI) interface;

and

wherein the downlink asynchronous radio carrier signal is formatted according to at least one of a Common Public Radio Interface (CPRI) standard, an Open Base Station Architecture Initiative (OBSAI) standard, and an Open Radio Interface (ORI) standard.

16. The signal interface unit of claim 1, wherein the downlink digital radio frequency signal contains a digital representation of the radio carrier positioned within a set of spectrum that reflects its eventual location within radio frequency spectrum.

17. The signal interface unit of claim 1, further comprising:

wherein the antenna side interface is configured to receive at least one of an uplink digitized radio frequency signal and an uplink channelized radio carrier signal from the antenna unit;

wherein the clock conversion unit is further configured to re-clock the uplink channelized radio carrier signal to the clock of the external device from the master clock of the radio system; and

wherein the external device interface is further configured to communicate an uplink channelized radio carrier signal for the radio frequency carrier to the external device.

18. A method comprising:

receiving a downlink asynchronous radio carrier signal for a radio frequency carrier at a signal interface unit from an external device;

re-clocking the downlink asynchronous radio carrier signal to a master clock of the radio system from the clock of the external device at the signal interface unit; and

communicating at least one of the re-clocked downlink asynchronous radio carrier signal and a downlink digitized radio frequency signal based on the re-clocked downlink asynchronous radio carrier signal from the signal interface unit to an antenna unit.

19. The method of claim 18, wherein re-clocking the downlink asynchronous radio carrier signal to a master clock of the radio system from the clock of the external device at the signal interface unit occurs at least in part through a resampling filter.

20. The method of claim 18, wherein re-clocking the downlink asynchronous radio carrier signal to a master clock of the radio system from the clock of the external device at the signal interface unit includes converting from a first clock domain of the external device to a second clock domain of the radio system using a Farrow structure.

21. The method of claim 18, wherein re-clocking the downlink asynchronous radio carrier signal to a master clock of the radio system from the clock of the external device at the signal interface unit includes converting first samples of a channelized radio carrier synchronous with a first clock of a first clock domain to second samples synchronous with a second clock of a second clock domain.

22. The method of claim 18, wherein the downlink asynchronous radio carrier signal is specific to a particular channel and requires additional baseband conversion before radio frequency conversion and transmission can be performed;

and

wherein the downlink digitized radio frequency signal is not specific to a particular channel and does not require additional baseband conversion before radio frequency conversion and transmission can be performed.

23. The method of claim 18, wherein the downlink asynchronous radio carrier signal includes I/Q pairs.

24. The method of claim 18, further comprising:

generating the downlink digitized radio frequency signal based on the re-clocked downlink asynchronous radio carrier signal.

25. The method of claim 18, wherein the antenna unit is a remote antenna unit communicatively coupled to the signal interface unit by at least one medium.

26. The method of claim 25, wherein communicating the at least one of the re-clocked downlink asynchronous radio carrier signal and a downlink digitized radio frequency signal based on the re-clocked downlink asynchronous radio carrier signal from the signal interface unit to an antenna unit occurs across the at least one medium.

27. The method of claim 25, further comprising aggregating the downlink digital radio frequency signal with at least one other downlink digital radio frequency signal at an intermediary device communicatively coupled between the signal interface and the remote antenna unit before being transmitted to the remote antenna unit.

28. The method of claim 27, wherein individual channels within the downlink digital radio frequency signal and the at least one other downlink digital radio frequency signal do not overlap and can be upconverted together simultaneously to radio frequency spectrum.

29. The method of claim 18, wherein the external device is part of a base band unit of a base station.

30. The method of claim 18, wherein the external device is at least one of a Common Public Radio Interface (CPRI) base station interface, an Open Base Station Architecture Initiative (OBSAI) base station interface, and an Open Radio Interface (ORI) interface;

and

wherein the downlink asynchronous radio carrier signal is formatted according to at least one of a Common Public Radio Interface (CPRI) standard, an Open Base Station Architecture Initiative (OBSAI) standard, and an Open Radio Interface (ORI) standard.

31. The method of claim 18, wherein the downlink digital radio frequency signal contains a digital representation of the radio carrier positioned within a set of spectrum that reflects its eventual location within radio frequency spectrum.

32. The method of claim 18, further comprising:

receiving at least one of an uplink digitized radio frequency signal and an uplink channelized radio carrier signal from the antenna unit at the signal interface;

re-clocking the uplink channelized radio carrier signal to the clock of the external device from the master clock of the radio system at the signal interface; and

communicating an uplink channelized radio carrier signal for the radio frequency carrier to the external device from the signal interface unit.

33. A distributed antenna system, comprising:

a plurality of signal interface units configured to receive a plurality of downlink asynchronous radio carrier signals for a plurality of radio frequency carriers from at least one external device, each of the plurality of downlink asynchronous radio carrier signals having a different clock;

wherein the plurality of signal interface units is further configured to re-clock the plurality of downlink asynchronous radio carrier signals to a master clock of the distributed antenna system from each different clock of each of the plurality of downlink asynchronous radio carrier signal;

wherein the plurality of signal interface units is further configured to convert the plurality of downlink asynchronous radio carrier signals to downlink digitized radio frequency signals;

a host unit communicatively coupled to the plurality of signal interface units and configured to combine at least two of the plurality of downlink digitized radio frequency signals into an aggregate downlink digitized radio frequency signal;

an antenna unit communicatively coupled to the host unit and configured to receive the aggregate downlink digitized radio frequency signal from the host unit;

wherein the antenna unit is further configured to convert at least one of the aggregate downlink digitized radio frequency signal and another signal based on the aggregate downlink digitized radio frequency signal into downlink radio frequency signals;

wherein the antenna unit is further configured to wirelessly transmit the downlink radio frequency signals to at least one subscriber unit.

34. The distributed antenna system of claim 33, wherein the plurality of signal interface units includes at least one resampling filter that re-clocks the plurality of downlink asynchronous radio carrier signals to the master clock of the remote antenna unit from each different clock of each of the plurality of downlink asynchronous radio carrier signal.

35. The distributed antenna system of claim 33, wherein the plurality of signal interface units is configured to convert from first clock domains of the external devices to a second clock domain of the remote antenna unit using a Farrow structure.

36. The distributed antenna system of claim 33, wherein at least one of the plurality of signal interface units is configured to re-clock at least one downlink asynchronous radio carrier signal by converting first samples of a channelized radio carrier synchronous with a first clock of a first clock domain to second samples synchronous with a second clock of a second clock domain.

37. The distributed antenna system of claim 33, wherein at least one of the plurality of downlink asynchronous radio carrier signals is specific to a particular channel and requires additional baseband conversion before radio frequency conversion and transmission can be performed;

and

wherein the aggregate downlink analog intermediate frequency signal is not specific to a particular channel and does not require additional baseband conversion before radio frequency conversion and transmission can be performed.

38. The distributed antenna system of claim 33, wherein at least one of the downlink asynchronous radio carrier signals includes I/Q pairs.

39. The distributed antenna system of claim 33, wherein individual channels within the at least two of the plurality of downlink analog intermediate frequency signals do not overlap and can be upconverted together simultaneously to radio frequency spectrum once combined into the aggregate downlink analog intermediate frequency signal.

40. The distributed antenna system of claim 33, wherein at least one of the plurality of external devices is a baseband processing unit of a base station.

41. The distributed antenna system of claim 33, wherein at least one of the plurality of downlink asynchronous radio carrier signals received at the plurality of signal interface units uses at least one of a SONET protocol and an Ethernet protocol to receive I/Q pairs.

42. The distributed antenna system of claim 33, wherein at least one of the plurality of network interfaces is at least one of a Common Public Radio Interface (CPRI) base station interface, an Open Base Station Architecture Initiative (OBSAI) base station interface, and an Open Radio Interface (ORI) interface;

and

wherein at least one of the downlink asynchronous radio carrier signal is formatted according to at least one of a Common Public Radio Interface (CPRI) standard, an Open Base Station Architecture Initiative (OBSAI) standard, and an Open Radio Interface (ORI) standard.

43. The distributed antenna system of claim 33, wherein at least one of the downlink asynchronous radio carrier signal contains a digital representation of a radio carrier positioned within a set of spectrum that reflects its eventual location within radio frequency spectrum.

44. The distributed antenna system of claim 33, further comprising:

wherein the plurality of signal interface units is further configured to convert a plurality of uplink digitized radio frequency signals to uplink asynchronous radio carrier signals at least in part by re-clocking a plurality of the uplink digitized radio frequency signals to a plurality of asynchronous clocks, different from the master clock of the distributed antenna system.

45. A method for interfacing a plurality of asynchronous downlink asynchronous radio carrier signal in a distributed antenna system, comprising:

receiving a plurality of downlink asynchronous radio carrier signals for a plurality of radio frequency carriers at a plurality of signal interface units from at least one external device, each of the plurality of downlink asynchronous radio carrier signals having a different clock;

re-clocking the plurality of downlink asynchronous radio carrier signals to a master clock of the distributed antenna system from each different clock of each of the plurality of downlink asynchronous radio carrier signals at the plurality of signal interface units;

converting the plurality of downlink asynchronous radio carrier signals to downlink digitized radio frequency signals at the plurality of signal interface units;

communicating the downlink digitized radio frequency signals from the plurality of signal interface units to a host unit;

combining at least two of the plurality of downlink digitized radio frequency signals into an aggregate downlink digitized radio frequency signal at the host unit;

communicating the aggregate downlink digitized radio frequency signal from the host unit to an antenna unit; and

converting at least one of the aggregate downlink digitized radio frequency signal and another signal based on the aggregate downlink digitized radio frequency signal into downlink radio frequency signals at the antenna unit.

46. The method of claim 45, further comprising:

wirelessly transmitting the downlink radio frequency signals to at least one subscriber unit.

47. The method of claim 45, wherein re-clocking the plurality of downlink asynchronous radio carrier signals to the master clock of the antenna unit from each different clock of each of the plurality of downlink asynchronous radio carrier signals at the antenna unit occurs through at least one resampling filter.

48. The method of claim 45, wherein re-clocking the plurality of downlink asynchronous radio carrier signals to the master clock of the antenna unit converts the plurality of downlink asynchronous radio carrier signals from first clock domains of the plurality of channelized radio carrier signals to a second clock domain of the antenna unit using a Farrow structure.

49. The method of claim 45, wherein re-clocking the plurality of downlink asynchronous radio carrier signals to the master clock of the antenna unit includes converting first samples of a channelized radio carrier synchronous with a first clock of a first clock domain to second samples synchronous with a second clock of a second clock domain.

50. The method of claim 45, wherein each of the plurality of downlink asynchronous radio carrier signals is specific to a particular channel and requires additional baseband conversion before radio frequency conversion and transmission can be performed;

and

wherein the aggregate downlink analog intermediate frequency signal is not specific to a particular channel and does not require additional baseband conversion before radio frequency conversion and transmission can be performed.

51. The method of claim 45, wherein each of the downlink asynchronous radio carrier signal includes I/Q pairs.

52. The method of claim 45, wherein individual channels within the at least two of the plurality of downlink analog intermediate frequency signals do not overlap and can be upconverted together simultaneously to radio frequency spectrum once combined into the aggregate downlink analog intermediate frequency signal.

53. The method of claim 45, wherein at least one of the plurality of external devices is at least one of a baseband processing unit of a base station.

54. The method of claim 45, wherein receiving at least one of the plurality of downlink asynchronous radio carrier signals for the plurality of radio frequency carriers occurs using at least one of a SONET protocol and an Ethernet protocol to transmit I/Q pairs.

55. The method of claim 45, wherein at least one of the plurality of network interfaces is at least one of a Common Public Radio Interface (CPRI) base station interface, an Open Base Station Architecture Initiative (OBSAI) base station interface, and an Open Radio Interface (ORI) interface;

and

wherein at least one of the downlink asynchronous radio carrier signal is formatted according to at least one of a Common Public Radio Interface (CPRI) standard, an Open Base Station Architecture Initiative (OBSAI) standard, and an Open Radio Interface (ORI) standard.

56. The method of claim 45, wherein at least one of the downlink asynchronous radio carrier signal contains a digital representation of a radio carrier positioned within a set of spectrum that reflects its eventual location within radio frequency spectrum.

57. The method of claim 45, further comprising:

converting a plurality of uplink digitized radio frequency signals to uplink asynchronous radio carrier signals at the plurality of signal interface units at least in part by re-clocking a plurality of the uplink digitized radio frequency signals to a plurality of asynchronous clocks, different from the master clock of the distributed antenna system.

58. A remote antenna unit, comprising:

a plurality of network interfaces configured to receive a plurality of downlink asynchronous radio carrier signals for a plurality of radio frequency carriers from at least one external device, each of the plurality of downlink asynchronous radio carrier signals having a different clock;

at least one clock conversion unit communicatively coupled to the plurality of external device interfaces and configured to re-clock the plurality of downlink asynchronous radio carrier signals to a master clock of the remote antenna unit from each different clock of each of the plurality of downlink asynchronous radio carrier signal;

at least one intermediate frequency convertor communicatively coupled to the at least one clock conversion unit and configured to convert the plurality of downlink asynchronous radio carrier signals to downlink analog intermediate frequency signals;

at least one switching unit communicatively coupled to the at least one intermediate frequency convertor and configured to combine at least two of the plurality of downlink analog intermediate frequency signals into an aggregate downlink analog intermediate frequency signal;

at least one radio frequency converter communicatively coupled to the at least one intermediate frequency converter and configured to convert the aggregate downlink analog intermediate frequency signal into a downlink radio frequency signal;

at least one antenna communicatively coupled to the at least one radio frequency converter and configured to wireless transmit the downlink radio frequency signals to at least one subscriber unit.

59. The remote antenna unit of claim 58, wherein the at least one clock conversion unit includes at least one resampling filter that re-clocks the plurality of downlink asynchronous radio carrier signals to the master clock of the remote antenna unit from each different clock of each of the plurality of downlink asynchronous radio carrier signal.

60. The remote antenna unit of claim 58, wherein the at least one clock conversion unit converts from a first clock domain of an external device to a second clock domain of the remote antenna unit using a Farrow structure.

61. The remote antenna unit of claim 58, wherein the at least one clock conversion unit is configured to re-clock the plurality of downlink asynchronous radio carrier signals by converting first samples of a channelized radio carrier synchronous with a first clock of a first clock domain to second samples synchronous with a second clock of a second clock domain.

62. The remote antenna unit of claim 58, wherein the each of the plurality of downlink asynchronous radio carrier signals is specific to a particular channel and requires additional baseband conversion before radio frequency conversion and transmission can be performed;

and

wherein the aggregate downlink analog intermediate frequency signal is not specific to a particular channel and does not require additional baseband conversion before radio frequency conversion and transmission can be performed.

63. The remote antenna unit of claim 58, wherein each of the downlink asynchronous radio carrier signals includes I/Q pairs.

64. The remote antenna unit of claim 58, wherein individual channels within the at least two of the plurality of downlink analog intermediate frequency signals do not overlap and can be upconverted together simultaneously to radio frequency spectrum once combined into the aggregate downlink analog intermediate frequency signal.

65. The remote antenna unit of claim 58, wherein at least one of the plurality of external devices is at least one of a host signal interface and an intermediary device.

66. The remote antenna unit of claim 58, wherein at least one of the downlink asynchronous radio carrier signal contains a digital representation of a radio carrier positioned within a set of spectrum that reflects its eventual location within radio frequency spectrum.

67. The remote antenna unit of claim 58, further comprising:

wherein the at least one clock conversion unit is further configured to convert a plurality of uplink digitized radio frequency signals to uplink asynchronous radio carrier signals at least in part by re-clocking a plurality of uplink digitized radio frequency signals to a plurality of asynchronous clocks, different from the master clock of the remote antenna unit.

68. The remote antenna unit of claim 67, wherein downlink and uplink signals within a radio frequency band are in distinct spectrum and are separated in frequency using a Frequency Division Duplexing (FDD) scheme.

69. The remote antenna unit of claim 67, wherein downlink and uplink signals within a radio frequency band overlap in spectrum and are separated in time using a Time Division Duplexing (TDD) scheme.

70. A method for interfacing a plurality of asynchronous downlink asynchronous radio carrier signal at an antenna unit, comprising:

receiving a plurality of downlink asynchronous radio carrier signals for a plurality of radio frequency carriers from at least one external device at the antenna unit, each of the plurality of downlink asynchronous radio carrier signals having a different clock;

re-clocking the plurality of downlink asynchronous radio carrier signals to a master clock of the antenna unit from each different clock of each of the plurality of downlink asynchronous radio carrier signals at the antenna unit;

converting the plurality of downlink asynchronous radio carrier signals to downlink analog intermediate frequency signals at the antenna unit;

combining at least two of the plurality of downlink analog intermediate frequency signals into an aggregate downlink analog intermediate frequency signal at the antenna unit;

converting the aggregate downlink analog intermediate frequency signal into downlink radio frequency signals at the antenna unit;

wirelessly transmitting the downlink radio frequency signals from the antenna unit to at least one subscriber unit.

71. The method of claim 70, wherein re-clocking the plurality of downlink asynchronous radio carrier signals to the master clock of the antenna unit from each different clock of each of the plurality of downlink asynchronous radio carrier signals at the antenna unit occurs through a at least one resampling filter.

72. The method of claim 70, wherein re-clocking the plurality of downlink asynchronous radio carrier signals to the master clock of the antenna unit converts the plurality of downlink asynchronous radio carrier signals from first clock domains of the plurality of channelized radio carrier signals to a second clock domain of the antenna unit using a Farrow structure.

73. The method of claim 70, wherein re-clocking the plurality of downlink asynchronous radio carrier signals to the master clock of the antenna unit includes converting first samples of a channelized radio carrier synchronous with a first clock of a first clock domain to second samples synchronous with a second clock of a second clock domain.

74. The method of claim 70, wherein each of the plurality of downlink asynchronous radio carrier signals is specific to a particular channel and requires additional baseband conversion before radio frequency conversion and transmission can be performed;

and

wherein the aggregate downlink analog intermediate frequency signal is not specific to a particular channel and does not require additional baseband conversion before radio frequency conversion and transmission can be performed.

75. The method of claim 70, wherein each of the downlink asynchronous radio carrier signal includes I/Q pairs.

76. The method of claim 70, wherein individual channels within the at least two of the plurality of downlink analog intermediate frequency signals do not overlap and can be upconverted together simultaneously to radio frequency spectrum once combined into the aggregate downlink analog intermediate frequency signal.

77. The method of claim 70, wherein at least one of the plurality of external devices is at least one of a host signal interface and an intermediary device.

78. The method of claim 70, wherein at least one of the downlink asynchronous radio carrier signal contains a digital representation of a radio carrier positioned within a set of spectrum that reflects its eventual location within radio frequency spectrum.

79. The method of claim 70, further comprising:

converting a plurality of uplink digitized radio frequency signals to uplink asynchronous radio carrier signals at the at least one clock conversion unit at least in part by re-clocking a plurality of uplink digitized radio frequency signals to a plurality of asynchronous clocks, different from the master clock of the remote antenna unit.