Backfire distributed antenna system (DAS) with delayed transport

• US 8,676,214 B2
• Filed: 02/09/2010
• Issued: 03/18/2014
• Est. Priority Date: 02/12/2009
• Status: Active Grant

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Fischer, Larry G., Tolstrup, Morten
• Primary Examiner(s): MITCHELL, NATHAN A
• Application Number:
  US12/702,784
• Publication Number:
  US 20100202356A1
• Time in Patent Office: 1,498 Days
• Field of Search: 455/422.1, 455/424, 455/425, 455/442, 455/448, 455/11.1, 455/16, 455/19, 455/25, 455/41.1, 455/41.2, 455/506, 455/524, 455/63.4, 455/562.1
• US Class Current: 455/442
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

A distributed antenna system (DAS) is provided, comprising a host unit and a plurality of remote placed to define a common coverage area. Each of the plurality of remote units is communicatively coupled to the host unit, points at least partially towards the common coverage area, and simulcasts data from the host unit.

Claims

1. A distributed antenna system (DAS), comprising:

a host unit; and

a plurality of remote units wherein the plurality of remote units are paired, wherein a pair of remote units are placed to define a common coverage area and each remote unit in a pair of remote units;

is communicatively coupled to the host unit;

points at least partially towards the remote unit to which it is paired, wherein each remote unit in the pair of remote units is spaced from the remote unit to which it is paired such that near each remote unit in the pair of remote units, a signal from the remote unit to which it is paired is negligible and the signal strength through the common coverage area is approximately constant, wherein the common coverage area is isolated from adjacent common coverage areas; and

simulcasts data from the host unit on the same frequency band as the remote unit to which it is paired.

2. The system of claim 1, wherein the host unit further comprises:

a processing unit operable to;

calculate a first delay of a signal path from the host unit to a first remote unit of each pair of remote units;

calculate a second delay of a signal path from the host unit to a second remote unit of each pair of remote units;

delay the signal from the host unit to the second remote unit such that the delayed signal arrives at the second remote unit at least one chip transmission time after the signal arrives at the first remote unit; and

broadcast the signal and the delayed signal approximately simultaneously; and

a memory coupled to the processing unit.

3. The system of claim 2, wherein the timing of the delayed version of the signal is sufficient such that a rake receiver in a mobile unit can resolve the signal and the delayed version of the signal.

4. The system of claim 1, wherein the pair of remote units point inward to the common coverage area.

5. The system of claim 1, wherein the host unit further comprises:

a network interface to communicatively couple with a base station transceiver.

6. The system of claim 1, wherein the plurality of remote units operate on the same frequency band.

7. The system of claim 1, wherein each remote unit pair is on a frequency band distinct from that of the other remote unit pairs.

8. The system of claim 1, wherein simulcast data from the host unit further comprises:

a first remote unit transmitting a signal with delay X; and

a second remote unit transmitting the signal with delay X+Y, where Y is greater than the transmission time for a single chip.

9. The system of claim 1, wherein the remote units are placed in a shape selected from the group consisting of approximately curvilinear, rectangular, square, diamond, hexagonal, octagonal, toroidal, and circular.

10. The system of claim 1, wherein the DAS is providing high-speed downlink packet access (HSDPA) to the coverage area.

11. The system of claim 1, wherein the DAS uses Space Time Coding (STC).

12. The system of claim 1, wherein the DAS uses Spatial Multiplexing (SM).

13. The system of claim 1, wherein the plurality of remote units comprises four remote units wherein the remote units are placed around the periphery of a building.

14. The system of claim 1, wherein the host is communicatively coupled to the base station transceiver using a transport medium selected from the group consisting of coaxial cable, fiber optic connections, twisted pair, free space optics, cable, mmWave, and radio frequency (RF) links.

15. The system of claim 1, wherein the plurality of antennas are communicatively coupled to the host using a transport medium selected from the group consisting of coaxial cable, fiber optic connections, twisted pair, free space optics, cable, mmWave, and radio frequency (RF) links.

16. A method for transmitting signals in a common coverage area, the method comprising:

calculating a first delay of a signal path from a host unit to a first remote unit of a pair of remote units, wherein the pair of remote units are placed to define a common coverage area;

calculating a second delay of a signal path from the host unit to a second remote unit of the pair of remote units, wherein the second remote unit is spaced from the first remote unit such that near the first remote unit the signal from the second remote unit is negligible and near the second remote unit the signal from the first remote unit is negligible, and a signal strength through the common coverage area is approximately constant, wherein the common coverage area is isolated from adjacent common coverage areas;

delaying the signal from the host unit to the second remote unit such that the delayed signal arrives at the second remote unit at least one chip transmission time after the signal arrives at the first remote unit; and

broadcasting the signal and the delayed signal approximately simultaneously.

17. The method of claim 16, wherein broadcasting the signal and the delayed signal further comprises broadcasting them over a common frequency band.

18. The method of claim 16, wherein broadcasting the signal and the delayed signal approximately simultaneously further comprises using Space Time Coding (STC).

19. The method of claim 16, wherein broadcasting the signal and the delayed signal approximately simultaneously further comprises using Spatial Multiplexing (SM).

20. A computer program product, comprising:

a non-transitory computer readable medium having instructions stored thereon for a method of transmitting signals in a common coverage area, the method comprising;

calculating a first delay of a signal path from a host unit to a first remote unit of a pair of remote units, wherein the pair of remote units are placed to define a common coverage area;

calculating a second delay of a signal path from the host unit to a second remote unit of a pair of remote units, wherein the second remote unit is spaced from the first remote unit such that near the first remote unit the signal from the second remote unit is negligible and near the second remote unit the signal from the first remote unit is negligible, and a signal strength through the common coverage area is approximately constant, wherein the common coverage area is isolated from adjacent common coverage areas;

delaying the signal from the host unit to the second remote unit such that the delayed signal arrives at the second remote unit at least one chip transmission time after the signal arrives at the first remote unit; and

broadcasting the signal and the delayed signal approximately simultaneously.

21. The computer program product of claim 20, wherein broadcasting the signal and the delayed signal further comprises broadcasting them over a common frequency band.

22. The computer program product of claim 20, wherein broadcasting the signal and the delayed signal approximately simultaneously further comprises using Space Time Coding (STC).

23. The computer program product of claim 20, wherein broadcasting the signal and the delayed signal approximately simultaneously further comprises using Spatial Multiplexing (SM).

24. A distributed antenna system (DAS), comprising:

a host unit; and

a plurality of remote units coupled to the host unit, the plurality of remote units placed to define a common coverage area wherein the plurality of remote units;

point at least partially inwards towards the common coverage area, wherein the common coverage area formed by the plurality of remote units is isolated from adjacent coverage areas formed by remote units in the DAS;

are widely spaced from each other such that near each remote unit in the plurality of remote units, signals from other remote units in the plurality of remote units are negligible, wherein the signal strength within the common coverage area is approximately constant; and

are paired to use multiple-input, multiple-output (MIMO) techniques.

25. The system of claim 24, wherein the host unit is configured to distribute orthogonal frequency division multiple access (OFDMA) signals.

26. The system of claim 24, wherein the MIMO network uses space time coding (STC).

27. The system of claim 26, wherein using space time coding further comprises the Alamouti method of channel coding using space-time block codes to transmit a copy of the signal to each remote unit.

28. The system of claim 24, wherein the MIMO network uses spatial multiplexing (SM).

29. The system of claim 24, wherein the plurality of remote units further comprises pairing a first remote unit with a second remote unit wherein each pair of remote units broadcasts on a common frequency band.

30. A method for transmitting signals in a coverage area, the method comprising:

calculating signal path delay from a host unit to each of a plurality of remote units;

transmitting a signal from the host unit to each of the plurality of remote units;

broadcasting the signal from each of the plurality of remote units approximately simultaneously into a common coverage area based on the calculated signal path delays using multiple-input-multiple-output (MIMO) techniques, wherein the plurality of remote units is widely spaced from each other such that near each remote unit in the plurality of remote units, signals from other remote units in the plurality of remote units are negligible and the common coverage area is isolated from adjacent coverage areas formed by remote units coupled to the host unit, wherein the signal strength within the common coverage area is approximately constant.

31. The method of claim 30, broadcasting a signal further comprises using orthogonal frequency division multiple access (OFDMA).

32. The method of claim 30, broadcasting the signal further comprises using space time coding (STC).

33. The network of claim 32, wherein using space time coding further comprises the Alamouti method of channel coding using space-time block codes to transmit a copy of the signal to each remote unit.

34. The network of claim 30, broadcasting the signal further comprises using spatial multiplexing (SM).

35. A distributed antenna system (DAS), comprising:

a host unit; and

a plurality of remote units wherein each of the plurality of remote units;

is communicatively coupled to the host unit;

points at least partially towards a common coverage area such that the common coverage area is isolated from adjacent coverage areas, wherein the signal strength within the common coverage area is approximately constant; and

simulcasts data from the host unit.

36. The system of claim 35, wherein simulcasts data from the host unit further comprises at least a first remote unit simulcasts on the same frequency band as a second remote unit.

37. The system of claim 35, wherein simulcasts data from the host unit further comprises wherein each of the plurality of remote units receives the data with a timing offset different from the data received by each other of the plurality of remote units;

and

wherein the timing offset between the data received by each remote unit is at least one chip apart from the data received by every other remote unit.

38. The system of claim 37, wherein the timing offset is achieved by one of a digital delay, an analog delay, or combinations thereof.

39. The system of claim 35, wherein the host unit further comprises:

a processing unit operable to;

calculate a first delay of a signal path from the host unit to a first remote unit of the plurality of remote units;

calculate a second delay of a signal path from the host unit to a second remote unit of the plurality of remote units;

delay the signal from the host unit to the second remote unit such that the delayed signal arrives at the second remote unit at least one chip transmission time after the signal arrives at the first remote unit; and

broadcast the signal and the delayed signal approximately simultaneously; and

a memory coupled to the processing unit.

40. The system of claim 39, wherein the timing of the delayed version of the signal is sufficient such that a rake receiver in a mobile unit can resolve the signal and the delayed version of the signal.

41. The system of claim 35, wherein the plurality of remote units operate on the same frequency band.

42. The system of claim 35, wherein each remote unit pair is on a frequency band distinct from that of the other remote unit pairs.

43. The system of claim 35, wherein the DAS is providing high-speed downlink packet access (HSDPA) to the coverage area.

44. The system of claim 35, wherein the DAS uses one of space time coding (STC) and spatial multiplexing (SM).

45. A method for transmitting signals in a common coverage area, the method comprising:

calculating a first delay of a signal path from a host unit to a first remote unit of a plurality of remote units, wherein the plurality of remote units are placed to define a common coverage area;

calculating a second delay of a signal path from the host unit to a second remote unit of the plurality of remote units, wherein the second remote unit is spaced from the first remote unit such that near the first remote unit the signal from the second remote unit is negligible and near the second remote unit the signal from the first remote unit is negligible, and a signal strength through the common coverage area is approximately constant, wherein the common coverage area is isolated from adjacent common coverage areas;

delaying the signal from the host unit to the second remote unit such that the delayed signal arrives at the second remote unit at least one chip transmission time after the signal arrives at the first remote unit; and

broadcasting the signal and the delayed signal approximately simultaneously.

46. The method of claim 45, wherein broadcasting the signal and the delayed signal further comprises broadcasting them over a common frequency band.

47. The method of claim 45, wherein broadcasting the signal and the delayed signal approximately simultaneously further comprises using one of space time coding (STC) and spatial multiplexing (SM).

48. A distributed antenna system (DAS), comprising:

a host unit, wherein the host unit provides a data signal to a first remote unit and a second remote unit;

a radiating cable, wherein;

a first end of the radiating cable is coupled to the first remote unit and a second end of the radiating cable is coupled to the second remote unit to define a common coverage area;

the first remote unit sends the data signal on a forward path of the radiating cable; and

the second remote unit sends a delayed data signal on a reverse path of the radiating cable, wherein the delayed data signal is the data signal with a timing offset,

wherein the second remote unit is spaced from the first remote unit such that near the first remote unit the signal from the second remote unit is negligible and near the second remote unit the signal from the first remote unit is negligible, and a signal strength through the common coverage area is approximately constant, wherein the common coverage area is isolated from adjacent common coverage areas.

49. The DAS of claim 48, wherein the timing offset is at least one chip.

50. The DAS of claim 48, wherein the radiating cable is installed in one of a tunnel, a building, and a mass transit rail line.

51. The DAS of claim 48, further comprising:

a second radiating cable; and

wherein the first radiating cable radiates a first component of a spatially multiplexed data signal and second radiating cable radiates a second component of the spatial multiplexed data signal.

52. A program product for transmitting signals in a common coverage area, the program-product comprising a non-transitory processor-readable medium on which program instructions are embodied, wherein the program instructions are operable, when executed by at least one programmable processor included in a host unit, to cause the host unit to:

calculate a first delay of a signal path from a host unit to a first remote unit of a plurality of remote units, wherein the plurality of remote units are placed to define a common coverage area;

calculate a second delay of a signal path from the host unit to a second remote unit of a plurality of remote units, wherein the second remote unit is spaced from the first remote unit such that near the first remote unit the signal from the second remote unit is negligible and near the second remote unit the signal from the first remote unit is negligible, and a signal strength through the common coverage area is approximately constant, wherein the common coverage area is isolated from adjacent common coverage areas;

delay the signal from the host unit to the second remote unit such that the delayed signal arrives at the second remote unit at least one chip transmission time after the signal arrives at the first remote unit; and

broadcast the signal and the delayed signal approximately simultaneously.

53. The computer program product of claim 52, wherein broadcast the signal and the delayed signal further comprises broadcasting the signal and the delayed signal over a common frequency band.

54. The computer program product of claim 52, wherein broadcasting the signal and the delayed signal approximately simultaneously further comprises using Space Time Coding (STC).

55. The computer program product of claim 52, wherein broadcasting the signal and the delayed signal approximately simultaneously further comprises using Spatial Multiplexing (SM).

56. A mobile device, comprising:

at least one transmitter; and

a rake receiver, wherein the rake receiver comprises a plurality of fingers, wherein the plurality of fingers resolves a first data signal from a second data signal, wherein the first and second data signals are received within a common coverage area of a backfire distributed antenna system, wherein the coverage area is isolated from adjacent coverage areas in the backfire distributed antenna system and the signal strength through the common coverage area is approximately constant.

57. The mobile device of claim 56, wherein the first data signal and the second data signal comprise the same signal with a timing offset of at least one chip.

58. The mobile device of claim 56, wherein the first and second data signals are within a first frequency band and have polarization diversity.

59. The mobile device of claim 56, wherein the backfire distributed antenna system comprises a plurality of base stations operating in a simulcast mode.

60. A distributed antenna system, comprising:

a host unit configured to simulcast at least one data signal; and

a plurality of remote units coupled to the host unit, wherein the plurality of remote units define a plurality of coverage areas wherein the plurality of coverage areas are isolated from one another, wherein;

each of the plurality of remote units comprises at least one antenna;

a first set of the plurality of remote units receives a first data signal; and

a second set of the plurality of remote units receives a second data signal;

wherein the first and second data signals are broadcasted approximately simultaneously from the at least one antenna of each of the plurality of remote units to form a common coverage area in the plurality of coverage areas;

wherein each of the plurality of remote units comprises a first antenna and a second antenna spaced apart to employ multiple-input-multiple-output functionality;

wherein the first set of the plurality of remote units receives a third data signal, wherein the first data signal is transmitted by the first antenna of each remote unit in the first set of the plurality of remote units and the third data signal is transmitted by the second antenna of each remote unit in the first set of the plurality of remote units; and

wherein the second set of the plurality of remote units receives a fourth data signal, wherein the second data signal is transmitted by the first antenna of each remote unit in the second set of the plurality of remote units and the fourth data signal is transmitted by the second antenna of each remote unit in the second set of the plurality of remote units.

61. The distributed antenna system of claim 60, further comprising:

a plurality of digital to analog radio frequency transceiver (DART) modules coupled to the host unit, wherein each DART module provides a signal to the host unit on a distinct channel.

62. The distributed antenna system of claim 60, further comprising:

wherein the first data signal is broadcasted approximately simultaneously from each of the remote units in the first set of the plurality of remote units; and

wherein the second data signal is broadcasted approximately simultaneously from each of the remote units in the second set of the plurality of remote units.

63. The distributed antenna system of claim 60, further comprising:

wherein the first data signal is broadcasted from each of the remote units in the first set of the plurality of remote units with a first timing offset; and

wherein the second data signal is broadcasted from each of the remote units in the second set of the plurality of remote units with a second timing offset.

64. The distributed antenna system of claim 60, wherein a remote unit from the second set of the plurality of remote units is located between a first remote unit from the first set of the plurality of remote units and a second remote unit from the first set of the plurality of remote units.