Symmeric sweep phase sweep transmit Diversity

• US 20030022635A1
• Filed: 07/30/2001
• Published: 01/30/2003
• Est. Priority Date: 07/30/2001
• Status: Active Grant

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Soni, Robert Atmaram, Polakos, Paul Anthony, Benning, Roger David, Buehrer, R. Michael
• Granted Patent: US 6,920,314 B2
• Time in Patent Office: Days
• US Class Current: 455/101
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0678 using different spreading codes between antennas code allocation H04J13/16

Abstract

Described herein is a method and apparatus for transmission that provides the performance of space time spreading (STS) or orthogonal transmit diversity (OTD) and the backwards compatibility of phase sweep transmit diversity (PSTD) without degrading performance of either STS or PSTD using a symmetric sweep PSTD transmission architecture. In one embodiment, a pair of signals s₁, and s₂ are split into signals s₁(a) and s₁(b) and signals s₂(a) and s₂(b), respectively. Signal s₁ comprises a first STS/OTD signal belonging to an STS/OTD pair, and signal s₂ comprises a second STS/OTD signal belonging to the STS/OTD pair. Signals s₁(b) and s₂(b) are phase swept using a pair of phase sweep frequency signals that would cancel out any self induced interference. For example, the pair of phase sweep frequency signals utilize a same phase sweep frequency with one of the phase sweep frequency signals rotating in the opposite direction plus an offset of π relative to the other phase sweep frequency signal. The resultant phase swept signals s₁(b) and s₂(b) are added to signals s₂(a) and s₁(a) before being amplified and transmitted.

Claims

1. A method of signal transmission comprising the steps of:

splitting a signal s₁ into signals s₁(a) and s₁(b), wherein signal s₁ comprises a first STS/OTD signal belonging to an STS/OTD pair;

splitting a signal s₂ into signals s₂(a) and s₂(b), wherein signal s₂ comprises a second STS/OTD signal belonging to the STS/OTD pair;

phase sweeping the signal s₁(b) using a first phase sweep frequency signal to produce a phase swept signal s₁(b);

phase sweeping the signal s₂(b) using a second phase sweep frequency signal to produce a phase swept signal s₂(b), the first and second phase sweep frequency signals being configured to cancel out any self induced interference caused by phase sweeping the signals s₁(b) and s₂(b);

adding the phase swept signal s₂(b) to the signal s₁(a) to produce a summed signal s₃; and

adding the phase swept signal s₁(b) to the signal s₂(a) to produce a summed signal S4.

2. The method of claim 1, wherein the first and second phase sweep frequency signals utilize a same phase sweep frequency with the second phase sweep frequency signal rotating in the opposite direction plus an offset of π

relative to the first phase sweep frequency signal.

3. The method of claim 1, wherein the first and second phase sweep frequency signals utilize a same phase sweep frequency with the first phase sweep frequency signal rotating in the opposite direction plus an offset of π

relative to the second phase sweep frequency signal.

4. The method of claim 1 comprising the additional steps of:

amplifying the summed signal s₃ to produce an amplified summed signal s₃; and

amplifying the summed signal s₄ to produce an amplified summed signal s₄.

5. The method of claim 1 comprising the additional steps of:

transmitting the summed signal s₃ over a first antenna belonging to a pair of diversity antennas; and

transmitting the summed signal s₄ over a second antenna belonging to the pair of diversity antennas.

6. The method of claim 1 comprising the additional steps of:

prior to the step of adding the phase swept signal s₂(b) to the signal s₁(a), phase sweeping the signal s₁ (a) using a third phase sweep frequency signal to produce a phase swept signal s₁(a) with a different phase from the phase swept signal s₂(b); and

prior to the step of adding the phase swept signal s₁(b) to the signal s₂(a), phase sweeping the signal s₂(a) using a fourth phase sweep frequency signal to produce a phase swept signal s₂(a) with a different phase from the phase swept signal s₁(b).

7. A method of signal transmission comprising the steps of:

splitting a signal s₁ into signals s₁(a) and s₁(b), wherein signal s₁ comprises a first STS/OTD signal belonging to an STS/OTD pair;

splitting a signal s₂ into signals s₂(a) and s₂(b), wherein signal s₂ comprises a second STS/OTD signal belonging to the STS/OTD pair;

phase sweeping the signal s₁(a) using a first phase sweep frequency signal to produce a phase swept signal s₁(a);

phase sweeping the signal s₂(a) using a second phase sweep frequency signal to produce a phase swept signal s₂(a), the first and second phase sweep frequency signals being configured to cancel out any self induced interference caused by phase sweeping the signals s₁(a) and s₂(a);

adding the phase swept signal s₂(a) to the signal s₁(b) to produce a summed signal s₃; and

adding the phase swept signal s₁(a) to the signal s₂(b) to produce a summed signal s₄.

8. The method of claim 7, wherein the first and second phase sweep frequency signals utilize a same phase sweep frequency with the second phase sweep frequency signal rotating in the opposite direction plus an offset of π

relative to the first phase sweep frequency signal.

9. The method of claim 7, wherein the first and second phase sweep frequency signals utilize a same phase sweep frequency with the first phase sweep frequency signal rotating in the opposite direction plus an offset of π

relative to the second phase sweep frequency signal.

10. The method of claim 7 comprising the additional steps of:

amplifying the summed signal s₃ to produce an amplified summed signal s₃; and

amplifying the summed signal s₄ to produce an amplified summed signal s₄.

11. The method of claim 7 comprising the additional steps of:

transmitting the summed signal s₃ over a first antenna belonging to a pair of diversity antennas; and

transmitting the summed signal s₄ over a second antenna belonging to the pair of diversity antennas.

12. The method of claim 7 comprising the additional steps of:

prior to the step of adding the phase swept signal s₂(a) to the signal s₁(b), phase sweeping the signal s₁(b) using a third phase sweep frequency signal to produce a phase swept signal s₁(b) with a different phase from the phase swept signal s₂(a); and

prior to the step of adding the phase swept signal s₁(a) to the signal s₂(b), phase sweeping the signal s₂(b) using a fourth phase sweep frequency signal to produce a phase swept signal s₂(b) with a different phase from the phase swept signal s₁(a).

13. A base station comprising:

a first splitter for splitting a signal s₁ into signals s₁(a) and s₁(b), wherein signal s₁ comprises a first STS/OTD signal belonging to an STS/OTD pair;

a second splitter for splitting a signal s₂ into signals s₂(a) and s₂(b), wherein signal s₂ comprises a second STS/OTD signal belonging to the STS/OTD pair,

a first multiplier for phase sweeping the signal s₁(b) using a first phase sweep frequency signal to produce a phase swept signal s₁(b);

a second multiplier for phase sweeping the signal s₂(b) using a second phase sweep frequency signal to produce a phase swept signal s₂(b), the first and second phase sweep frequency signals being configured to cancel out any self induced interference caused by phase sweeping the signals s₁(b) and s₂(b);

a first adder for adding the phase swept signal s₂(b) to the signal s₁(a) to produce a summed signal s₃; and

a second adder for adding the phase swept signal s₁(b) to the signal s₂(a) to produce a summed signal s₄.

14. The base station of claim 13, wherein the first and second phase sweep frequency signals utilize a same phase sweep frequency with the second phase sweep frequency signal rotating in the opposite direction plus an offset of π

relative to the first phase sweep frequency signal.

15. The base station of claim 13, wherein the first and second phase sweep frequency signals utilize a same phase sweep frequency with the first phase sweep frequency signal rotating in the opposite direction plus an offset of π

relative to the second phase sweep frequency signal.

16. The base station of claim 13 further comprising:

a first amplifier for amplifying the summed signal s₃ to produce an amplified summed signal s₃; and

a second amplifier for amplifying the summed signal s₄ to produce an amplified summed signal s₄.

17. The base station of claim 13 further comprising:

a pair of diversity antennas having a first and a second antenna;

a first transmitter for transmitting the summed signal s₃ over the first antenna; and

a second transmitter for transmitting the summed signal s₄ over the second antenna.

18. The base station of claim 13 further comprising:

a third multiplier for phase sweeping the signal s₁(a) using a third phase sweep frequency signal to produce a phase swept signal s₁(a) with a different phase from the phase swept signal s₂(b) prior to adding the phase swept signal s₂(b) to the signal s₁(a); and

a fourth multiplier for phase sweeping the signal s₂(a) using a fourth phase sweep frequency signal to produce a phase swept signal s₂(a) with a different phase from the phase swept signal s₁(b) prior to adding the phase swept signal s₁(b) to the signal s₂(a).

19. A base station comprising:

a first splitter for splitting a signal s₁ into signals s₁(a) and s₁(b), wherein signal s₁ comprises a first STS/OTD signal belonging to an STS/OTD pair;

a second splitter for splitting a signal s₂ into signals s₂(a) and s₂(b), wherein signal s₂ comprises a second STS/OTD signal belonging to the STS/OTD pair;

a first multiplier for phase sweeping the signal s₁(a) using a first phase sweep frequency signal to produce a phase swept signal s₁(a);

a second multiplier for phase sweeping the signal s₂(a) using a second phase sweep frequency signal to produce a phase swept signal s₂(a), the first and second phase sweep frequency signals being configured to cancel out any self induced interference caused by phase sweeping the signals s₁(a) and s₂(a);

a first adder for adding the phase swept signal s₂(a) to the signal s₁(b) to produce a summed signal s₃; and

a second adder for adding the phase swept signal s₁(a) to the signal s₂(b) to produce a summed signal s₄.

20. The base station of claim 19, wherein the first and second phase sweep frequency signals utilize a same phase sweep frequency with the second phase sweep frequency signal rotating in the opposite direction plus an offset of π

relative to the first phase sweep frequency signal.

21. The base station of claim 19, wherein the first and second phase sweep frequency signals utilize a same phase sweep frequency with the first phase sweep frequency signal rotating in the opposite direction plus an offset of π

relative to the second phase sweep frequency signal.

22. The base station of claim 19 further comprising:

a first amplifier for amplifying the summed signal s₃ to produce an amplified summed signal s₃; and

a second amplifier for amplifying the summed signal s₄ to produce an amplified summed signal s₄.

23. The base station of claim 19 further comprising:

a pair of diversity antennas having a first and a second antenna;

a first transmitter for transmitting the summed signal s₃ over the first antenna; and

a second transmitter for transmitting the summed signal s₄ over the second antenna.

24. The base station of claim 19 further comprising:

a third multiplier for phase sweeping the signal s₁(b) using a third phase sweep frequency signal to produce a phase swept signal s₁(b) with a different phase from the phase swept signal s₂(a) prior to adding the phase swept signal s₂(a) to the signal s₁(b); and

a fourth multiplier for phase sweeping the signal s₂(b) using a fourth phase sweep frequency signal to produce a phase swept signal s₂(b) with a different phase from the phase swept signal s₁(a) prior to adding the phase swept signal s₁(a) to the signal s₂(b).