Split shift phase sweep transmit diversity
View Patent ↗Disclosed is a method and apparatus of transmit diversity that is backward compatible and does not degrade performance using a transmission architecture that incorporates a form of phase sweep transmit diversity (PSTD) referred to herein as split shift PSTD. Split shift PSTD involves transmitting at least two phase swept versions of a signal over diversity antennas, wherein the two phase swept versions of the signal have a different phase. The phase sweep frequency signals may have a fixed or varying phase shifting rate, may have an identical or different phase shifting rate, may be offset from each other and/or may be phase shifting in the same or opposite direction.
1. A method of signal transmission comprising the steps of:
splitting a signal s 1 into signals s 1 (a) and s 1 (b), wherein the signal s 1 is split unevenly such that the signal s 1 (a) has an associated power level greater than a power level associated with the signal s 1 (b);
phase sweeping the signal s 1 (a) using a first phase sweep frequency signal to produce a phase swept signal s 1 (a); and
phase sweeping the signal s 1 (b) using a second phase sweep frequency signal to produce a phase swept signal s 1 (b), wherein the phase swept signal s 1 (a) has a different phase from the phase swept signal s 1 (b).
2. The method of claim 1 , wherein the first phase sweep frequency signal phase sweeps the signal s 1 (a) in a direction opposite to a direction the second phase sweep frequency signal phase sweeps the signal s 1 (b).
3. The method of claim 2 , wherein a first phase sweep frequency associated with the first phase sweep frequency signal is identical to a second phase sweep frequency associated with the second phase sweep frequency signal.
4. The method of claim 2 , wherein a first phase sweep frequency associated with the first phase sweep frequency signal is not identical to a second phase sweep frequency associated with the second phase sweep frequency signal.
5. The method of claim 2 , wherein a first phase sweep frequency associated with the first phase sweep frequency signal is a fixed phase shifting rate.
6. The method of claim 2 , wherein a first phase sweep frequency associated with the first phase sweep frequency signal is a variable phase shifting rate.
7. The method of claim 2 , wherein a second phase sweep frequency associated with the second phase sweep frequency signal is a fixed phase shifting rate.
8. The method of claim 2 , wherein a second phase sweep frequency associated with the second phase sweep frequency signal is a variable phase shifting rate.
9. The method of claim 1 , wherein the first and second phase sweep frequency signals phase sweep the signals s 1 (a) and s 1 (b) in a same direction.
10. The method of claim 9 , wherein a first phase sweep frequency associated with the first phase sweep frequency signal is identical to a second phase sweep frequency associated with the second phase sweep frequency signal.
11. The method of claim 9 , wherein a first phase sweep frequency associated with the first phase sweep frequency signal is not identical to a second phase sweep frequency associated with the second phase sweep frequency signal.
12. The method of claim 1 comprising the additional step of:
amplifying the phase swept signals s 1 (a) and s 1 (b).
13. The method of claim 1 comprising the additional step of:
transmitting the phase swept signals s 1 (a) and s 1 (b) over a pair of diversity antennas.
14. A method of signal transmission comprising the steps of:
splitting a signal s 1 into signals s 1 (a) and s 1 (b), wherein the signal s 1 includes a communication signal;
phase sweeping the signal s 1 (a) using a first phase sweep frequency signal to produce a phase swept signal s 1 (a); and
phase sweeping the signal s 1 (b) using a second phase sweep frequency signal to produce a phase swept signal s 1 (b), wherein the phase swept signal s 1 (a) has a different phase from the phase swept signal s 1 (b), and the first phase sweep frequency signal phase sweeps the signal s 1 (a) in a direction opposite to a direction the second phase sweep frequency signal phase sweeps the signal s 1 (b).
15. The method of claim 14 , wherein a first phase sweep frequency associated with the first phase sweep frequency signal is identical to a second phase sweep frequency associated with the second phase sweep frequency signal.
16. The method of claim 14 , wherein a first phase sweep frequency associated with the first phase sweep frequency signal is not identical to a second phase sweep frequency associated with the second phase sweep frequency signal.
17. The method of claim 14 , wherein a first phase sweep frequency associated with the first phase sweep frequency signal is a fixed or a variable phase shifting rate.
18. The method of claim 14 , wherein a second phase sweep frequency associated with the second phase sweep frequency signal is a fixed or variable phase shifting rate.
19. The method of claim 14 comprising the additional step of:
amplifying the phase swept signals s 1 (a) and s 1 (b).