High-speed two-way point-to-point transmission

• US 7,620,375 B1
• Filed: 09/28/2005
• Issued: 11/17/2009
• Est. Priority Date: 07/10/2002
• Status: Expired due to Fees

• Current Assignee: AT&T Properties, LLC (AT&T, Inc.)
• Original Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Inventors: Clark, Martin Vivian, Darcie, Thomas Edward, Greenstein, Lawrence Joel, Martin, Carol Catalano, Willis, Thomas M. III
• Primary Examiner(s): Le; Nhan T
• Application Number:
  US11/237,047
• Time in Patent Office: 1,511 Days
• Field of Search: 455/101, 455/103, 455/105, 455/272, 455/276.1, 455/522, 455/59, 455/60, 455/63.1, 455/63.4
• US Class Current: 455/105
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Multiple-input/multiple-output (MIMO) antenna technology is used in a point-to-point radio link to provide higher data rates than would otherwise be achievable in a similar system that did not use MIMO antenna technology. Particular embodiments of the invention implement channel coding, dual polarization, adaptive receiver combining and adaptive power control.

Claims

1. An apparatus comprising

a first antenna system comprising at least first and second antennas installed at respective fixed locations, said first and second antennas each being aimed toward a second antenna system, and

transmitter means for applying to said first antenna a first radio-frequency signal having energy in a particular frequency band and representing a first data stream, and for applying to said second antenna a second radio-frequency signal having energy in said particular frequency band and representing a second data stream,

said first and second antennas being located with respect to each other and with respect to said second antenna system in such a way that at least two versions of said first radio-frequency signal, having substantially different phases, arrive at said second antenna system and in such a way that at least two versions of said second radio-frequency signal, having substantially different phases, arrive at said second antenna system,

wherein said second antenna system comprises at least third and fourth antennas,

wherein said at least two versions of said first radio-frequency signal arrive at said third and fourth antennas, respectively,

wherein said at least two versions of said second radio-frequency signal arrive at said fourth and third antennas, respectively,

and wherein said first antenna system is fixed at a distance D from said second antenna system and said first and second antennas are fixed at a distance L₁=λ

D/2 L₂ from one another, where λ

is a wavelength within said frequency band and L₂ is the distance between said third and fourth antennas.

2. The apparatus of claim 1 wherein said frequency band has a lower limit of at least 1.5 GHz.

3. The apparatus of claim 1 wherein said first antenna system is at least 1.5 km distant from said second antenna system and wherein said first and second antennas are separated from one another by at least 1 meter.

4. The apparatus of claim 1 wherein said transmitter means is adapted to independently channel-encode said first and second data streams and to modulate the encoded first and second data streams to generate said first and second radio-frequency signals.

5. The apparatus of claim 1 wherein said transmitter means includes

means for applying to said first antenna a third radio-frequency signal having energy in said particular frequency band and representing a third data stream, and wherein said first antenna transmits said first radio-frequency signal with a first polarization and said third radio-frequency signal with a second polarization and

means for applying to said second antenna a fourth radio-frequency signal having energy in said particular frequency band and representing a fourth data stream, and wherein said second antenna transmits said second radio-frequency signal with a first polarization and said fourth radio-frequency signal with a second polarization.

6. The apparatus of claim 1 wherein D is at least 1.5 km and wherein λ

is about 24 millimeters or less.

7. The apparatus of claim 1 wherein said apparatus includes receiver means for processing radio-frequency signals within said frequency band received at said first antenna system.

8. The apparatus of claim 1 wherein said first and second data streams have a combined bit rate of at least 622 Mb/s.

9. An apparatus comprising

first and second antenna systems installed at respective fixed locations,

transmitter circuitry adapted to apply to said first antenna system at least first and second first radio-frequency signals A and B having energy in a particular frequency band and representing first and second data streams, respectively,

said first and second antenna systems being such that signals A, Ā

, B and B arrive at said second antenna system, signal Ā

being a phase-delayed version of signal A and signal B being a phase-delayed version of signal B, and

receiver circuitry adapted to process the signals that arrive at said second antenna system in such a way as to recover said first and second data streams,

wherein each of said antenna systems comprises two or more spaced-apart antennas, wherein signal A is applied to a first antenna of said first antenna system, signal B is applied to a second antenna of said first antenna system, said signals A and B arrive at a first antenna of said second antenna system and said signals B and Ā

arrive at a second antenna of said second antenna system,

and wherein said first antenna system is fixed at a distance D from said second antenna system and said first and second antennas of said first antenna system are fixed at a distance L₁=λ

D/2 L₂ from one another, where λ

is a wavelength within said frequency band and L₂ is the distance between the first and second antennas of said second antenna system.

10. The apparatus of claim 9 wherein

said transmitter means is further adapted to apply, to said first and second antennas, third and fourth radio-frequency signals, respectively, having energy in said particular frequency band and representing third and fourth data streams, respectively,

said first and second antennas are adapted to transmit said first and second radio-frequency signals with a first polarization and to transmit said third and fourth radio-frequency signals with a second polarization, and

said receiver circuitry is adapted to adaptively combine signals derived from the signals that arrive at said second antenna system in such a way as to recover said first, second, third and fourth data streams.

11. The apparatus of claim 9 wherein said first and second data streams have a combined bit rate of at least 622 Mb/s.

12. An apparatus comprising

a first antenna system comprising at least first and second antennas installed at respective fixed locations,

a second antenna system comprising at least third and fourth antennas installed at respective fixed locations,

said first and second antennas each being aimed toward said second antenna system and said third and fourth antennas each being aimed toward said first antenna system,

first transmitter means for applying to said first and second antennas respective raid-frequency signals each having energy in a particular one frequency band and each representing at least one respective data stream, and

second transmitter means for applying to said third and fourth antennas respective radio-frequency signals each having energy in a particular one frequency band and each representing at least one respective data stream,

said antennas being located with respect to each other in such a way that at least two versions of the radio-frequency signal launched by each antenna of each said antenna system arrive with substantially different phases at the other antenna system,

and said first antenna system being fixed at a distance D from said second antenna system and said first and second antennas being fixed at a distance of L₁=λ

D/2 L₂ from one another, where λ

is a wavelength within said frequency band and L₂ is the distance between said third and fourth antennas.

13. The apparatus of claim 12 wherein the particular one frequency band of said first and second radio-frequency signals is the same as the particular one frequency band of said third and fourth radio-frequency signal and wherein said first and second radio-frequency signals are transmitted at different times from said third and fourth radio-frequency signals.

14. The apparatus of claim 13 wherein each of said first, second, third and fourth radio-frequency signals is dual-polarized and represents at least first and second respective data streams on each of its polarizations.

15. The apparatus of claim 14 further comprising

first receiver means adapted to process the signals that arrive at said second antenna system in such a way as to recover the data streams carried by said first and second radio-frequency signals, and

second receiver means adapted to process the signals that arrive at said first antenna system in such a way as to recover the data streams carried by said third and fourth radio-frequency signals.

16. The apparatus of claim 15 wherein said first and second transmitter means operate in a time-division duplex mode in which said first and second transmitter means transmit at different times from one another.

17. The apparatus of claim 15 wherein said first transmitted means is adapted to independently channel-encode and modulate said at least one respective data stream.

18. A method comprising

applying to a first antenna of a first antenna system a first radio-frequency signal having energy in a particular frequency band and representing a first data stream, and

applying to a second antenna of said first antenna system a second radio-frequency signal having energy in said particular frequency band and representing a second data stream, said first and second antennas being installed at respective fixed locations and said first and second antennas each being aimed toward a second antenna system,

said first and second antennas being located with respect to each other and with respect to said second antenna system in such a way that at least two versions of said first radio-frequency signal, having substantially different phases, arrive at said second antenna system and in such a way that at least two versions of said second radio-frequency signal, having substantially different phases, arrive at said second antenna system,

wherein said second antenna system comprises at least third and fourth antennas,

wherein said at least two versions of said first radio-frequency signal arrive at said third and fourth antennas, respectively,

wherein said at least two versions of said second radio-frequency signal arrive at said fourth and third antennas, respectively,

and wherein said first antenna system is fixed at a distance D from said second antenna system and said first and second antennas are fixed at a distance L₁=λ

D/2 L₂ from one another, where λ

is a wavelength within said frequency band and L₂ is the distance between said third fourth antennas.

19. The method of claim 18 wherein said frequency band has a lower limit of at least 1.5 GHz.

20. The method of claim 18 wherein said first antenna system is at least 1.5 km distant from said second antenna system and wherein said first and second antennas are separated from one another by at least 1 meter.

21. The method of claim 18 further comprising

independently channel-encoding said first and second data streams, and

modulating the encoded first and second data streams to generate said first and second radio-frequency signals.

22. The method of claim 18 further comprising

applying to said first antenna a third radio-frequency signal having energy in said particular frequency band and representing a third data stream, said first antenna transmitting said first radio-frequency signal with a first polarization and said third radio-frequency signal with a second polarization, and

applying to said second antenna a fourth radio-frequency signal having energy in said particular frequency band and representing a fourth data stream, said second antenna transmitting said second radio-frequency signal with a first polarization and said fourth radio-frequency signal with a second polarization.

23. The method of claim 18 wherein D is at least 1.5 km and wherein λ

is about 24 millimeters or less.

24. The method of claim 18 further comprising processing radio-frequency signals within said frequency band received at said first antenna system.

25. The method of claim 18 wherein said first and second data streams have a combined bit rate of at least 622 Mb/s.

26. A method comprising

applying to said first and second antennas of a first antenna system respective radio-frequency signals each having energy in a particular one frequency band and each representing at least one respective data stream, said first and second antennas being installed at respective fixed locations,

applying to third and fourth antennas of a second antenna system respective radio-frequency signals each having energy in a particular one frequency band and each representing at least one respective data stream, said third and fourth antennas being installed at respective fixed locations,

said first and second antennas each being aimed toward said second antenna system and said third and fourth antennas each being aimed toward said first antenna system and said first, second, third and fourth antennas being located with respect to each other in such a way that at least two versions of the radio-frequency signal launched by each antenna of each said antenna system arrive with substantially different phases at the other antenna system,

wherein said first antenna system is fixed at a distance D from said second antenna system and said first and second antennas are fixed at a distance L₁=λ

D/2 L₂ from one another, where λ

is a wavelength within said frequency band and L₂ is the distance between said third and fourth antennas.

27. The method of claim 26 wherein the particular one frequency band of said first and second radio-frequency signals is the same as the particular one frequency band of said third and fourth radio-frequency signals and wherein said first and second radio-frequency signals are transmitted at different times from said third and fourth radio-frequency signals.

28. The method of claim 27 wherein each of said first, second, third and fourth radio-frequency signals is dual-polarized and represents at least first and second respective data streams on each of its polarizations.

29. The method of claim 28 further comprising

processing the signals that arrive at said second antenna system in such a way as to recover the data streams carried by said first and second radio-frequency signals, and

processing the signals that arrive at said first antenna system in such a way as to recover the data streams carried by said third and fourth radio-frequency signals.

30. The method of claim 29 wherein radio-frequency signals are applied to said first and second antennas at different times from when radio-frequency signals are applied to said third and fourth antennas.

31. The method of claim 29 further comprising independently channel-encoding and modulating each said data stream.

32. An apparatus comprising

a first antenna system comprising at least first and second antennas installed at respective fixed locations, said first and second antennas each being aimed toward a second antenna system, and

transmitter means for applying to said first antenna a first radio-frequency signal having energy in a particular frequency band and representing a first data stream, and for applying to said second antenna a second radio-frequency signal having energy in said particular frequency band and representing a second data stream,

said first and second antennas being located with respect to each other and with respect to said second antenna system in such a way that at least two versions of said first radio-frequency signal, having substantially different phases, arrive at said second antenna system and in such a way that at least two versions of said second radio-frequency signal, having substantially different phases, arrive at said second antenna system,

wherein said at least two versions of said first radio-frequency signal are two signals each having a carrier wavelength λ

and wherein those two signals differ in phase by substantially an odd multiple of λ

/2,

and wherein said at least two versions of said second radio-frequency signal are two signals each having said carrier wavelength λ and

wherein those two signals differ in phase by substantially said odd multiple of λ

/2.

33. An apparatus comprising

first and second antenna systems installed at respective fixed locations,

transmitter circuitry adapted to apply to said first antenna system at least first and second first radio-frequency signals A and B having energy in a particular frequency band and repenting first and second data streams, respectively,

said first and second antenna systems being such that signals A, Ā

, B and B arrive at said second antenna system, signal Ā

being a phase-delayed version of signal A and signal B being a phase-delayed version of signal B, and

receiver circuitry adapted to process the signals that arrive at said second antenna system in such a way as to recover said first and second data streams,

wherein signals A, Ā

, B and B each have a carrier wavelength λ

, wherein signal Ā

is a version of signal A phase-delayed by an odd multiple of λ

/2 and wherein signal B is a version of signal B phase-delayed by said odd multiple of λ

/2.

34. An apparatus comprising

a first antenna system comprising at least first and second antennas installed at respective fixed locations,

a second antenna system comprising at least third and fourth antennas installed at respective fixed locations,

said first and second antennas each being aimed toward said second antenna system and said third and fourth antennas each being aimed toward said first antenna system,

first transmitter means for applying to said first and second antennas respective radio-frequency signals each having energy in a particular one frequency band and each representing at least one respective data stream, and

second transmitter means for applying to said third and fourth antennas respective radio-frequency signals each having energy in a particular one frequency band and each representing at least one respective data stream,

said antennas being located with respect to each other in such a way that at least two versions of the radio-frequency signal launched by each antenna of each said antenna system arrive with substantially different phases at the other antenna system,

wherein said at least two versions of the radio-frequency signal launched by each antenna of each said antenna system each have a carrier wavelength λ

and differ by, substantially, an odd multiple of λ

/2.

35. A method comprising

applying to a first antenna of a first antenna system a first radio-frequency signal having energy in a particular frequency band and representing a first data stream, and

applying to a second antenna of said first antenna system a second radio-frequency signal having energy in said particular frequency band and representing a second data stream, said first and second antennas being installed at respective fixed locations and said first and second antennas each being aimed toward a second antenna system,

said first and second antennas being located with respect to each other and with respect to said second antenna system in such a way that at least two versions of said first radio-frequency signal, having substantially different phases, arrive at said second antenna system and in such a way that at least two versions of said second radio-frequency signal, having substantially different phases, arrive at said second antenna system,

wherein said at least two versions of said first radio-frequency signal are two signals each having a carrier wavelength λ

and wherein those two signals differ in phase by, substantially, an odd multiple of λ

/2,

and wherein said at least two versions of said second radio-frequency signal are two signals each having said carrier wavelength λ and

wherein those two signals differ in phase by, substantially, said odd multiple of λ

/2.

36. A method comprising

applying to said first and second antennas of a first antenna system respective radio-frequency signals each having energy in a particular one frequency band and each representing at least one respective data stream, said first and second antennas being installed at respective fixed locations, and

applying to third and fourth antennas of a second antenna system respective radio-frequency signals each having energy in a particular one frequency band and each representing at least one respective data stream, said third and fourth antennas being installed at respective fixed locations,

said first and second antennas each being aimed toward said second antenna system and said third and fourth antennas each being aimed toward said first antenna system and said first, second, third and fourth antennas being located with respect to each other in such a way that at least two versions of the radio-frequency signal launched by each antenna of each said antenna system arrive with substantially different phases at the other antenna system,

wherein said at least two versions of the radio-frequency signal launched by each antenna of each said antenna system each have a carrier wavelength λ

and arrive with phases that differ, substantially, by an odd multiple of λ

/2.