Phase rotation of IQ origin
View Patent ↗Sampled IQ values at the origin are revalued by applying a minimum distance, or radius, away from the (0,0) coordinate in the IQ domain, and applying a rotation about the origin for consecutive (0,0) samples, thereby improving communication performance. A direction of rotation is able to be predetermined or dynamically determined according to a correction look-up table or an IQ trajectory.
1. A method comprising:
a. sampling an input signal to generate a plurality of discrete sampled IQ values within an IQ domain, wherein each sampled IQ value includes an in-phase component and a quadrature component;
b. for a first sampled IQ value at the origin, revaluing the first sampled IQ value to a first revalued sampled IQ value, wherein the first revalued sample IQ value is a non-origin IQ value;
c. for each consecutive sampled IQ value at the origin that immediately follows the first sampled IQ value, rotating the first revalued sampled IQ value about the origin, thereby forming a next revalued sampled IQ value such that each next revalued sampled IQ value is an immediately preceding revalued sample IQ value rotated about the origin; and
modulating each sampled IQ value not originally at the origin and each revalued sampled IQ value, wherein a direction of rotation used to form each next revalued sampled IQ value is clockwise, thereby distributing more energy to a low frequency side of a carrier band than to a high frequency side.
2. The method of claim 1 wherein the non-origin IQ value is a predetermined value.
3. The method of claim 1 wherein the non-origin IQ value is a randomly selected value at least a predetermined radius away from the origin.
4. The method of claim 1 wherein a degree of rotation used to form each next revalued sampled IQ value is a predetermined amount.
5. The method of claim 1 wherein a degree of rotation used to form each next revalued sampled IQ value is 90 degrees.
6. The method of claim 1 wherein a degree of rotation used to form each next revalued sampled IQ value is a randomly selected amount.
7. The method of claim 1 wherein a degree of rotation used to form each next revalued sampled IQ value is constant.
8. The method of claim 1 wherein a degree of rotation used to form each next revalued sampled IQ value is independent for each revalued sampled IQ value.
9. The method of claim 1 wherein the non-origin IQ value is a predetermined value.
10. The method of claim 1 wherein the non-origin IQ value is a randomly selected value at least a predetermined radius away from the origin.
11. A method comprising:
a. sampling an input signal to generate a plurality of discrete sampled IQ values within an IQ domain, wherein each sampled IQ value includes an in-phase component and a quadrature component;
b. for a first sampled IQ value at the origin, revaluing the first sampled IQ value to a first revalued sampled IQ value, wherein the first revalued sample IQ value is a non-origin IQ value;
c. for each consecutive sampled IQ value at the origin that immediately follows the first sampled IQ value, rotating the first revalued sampled IQ value about the origin, thereby forming a next revalued sampled IQ value such that each next revalued sampled IQ value is an immediately preceding revalued sample IQ value rotated about the origin; and
d. modulating each sampled IQ value not originally at the origin and each revalued sampled IQ value,
wherein a direction of rotation used to form each next revalued sampled IQ value is counter-clockwise, thereby distributing more energy to a high frequency side of a carrier band than to a low frequency side.
12. The method of claim 11 wherein the non-origin IQ value is a predetermined value.
13. The method of claim 11 wherein the non-origin IQ value is a randomly selected value at least a predetermined radius away from the origin.
14. The method of claim 11 wherein a degree of rotation used to form each next revalued sampled IQ value is a predetermined amount.
15. The method of claim 11 wherein a degree of rotation used to form each next revalued sampled IQ value is 90 degrees.
16. The method of claim 11 wherein a degree of rotation used to form each next revalued sampled IQ value is a randomly selected amount.
17. The method of claim 11 wherein a degree of rotation used to form each next revalued sampled IQ value is constant.
18. The method of claim 11 wherein a degree of rotation used to form each next revalued sampled IQ value is independent for each revalued sampled IQ value.
19. A method comprising:
a. sampling an input signal to generate a plurality of discrete sampled IQ values within an IQ domain, wherein each sampled IQ value includes an in-phase component and a quadrature component;
b. for a first sampled IQ value at the origin, revaluing the first sampled IQ value to a first revalued sampled IQ value, wherein the first revalued sample IQ value is a non-origin IQ value;
c. for each consecutive sampled IQ value at the origin that immediately follows the first sampled IQ value, rotating the first revalued sampled IQ value about the origin, thereby forming a next revalued sampled IQ value such that each next revalued sampled IQ value is an immediately preceding revalued sample IQ value rotated about the origin; and
d. modulating each sampled IQ value not originally at the origin and each revalued sampled IQ value, and
wherein a direction of rotation used to form each next revalued sampled IQ value is determined according to a correction look-up table that includes a set of correction values, and if the correction look-up table includes a negative value corresponding to the origin, then the direction of rotation is counterclockwise.
20. A method comprising:
a. sampling an input signal to generate a plurality of discrete sampled IQ values within an IQ domain, wherein each sampled IQ value includes an in-phase component and a quadrature component;
b. for a first sampled IQ value at the origin, revaluing the first sampled IQ value to a first revalued sampled IQ value, wherein the first revalued sample IQ value is a non-origin IQ value;
c. for each consecutive sampled IQ value at the origin that immediately follows the first sampled IQ value, rotating the first revalued sampled IQ value about the origin, thereby forming a next revalued sampled IQ value such that each next revalued sampled IQ value is an immediately preceding revalued sample IQ value rotated about the origin; and
d. modulating each sampled IQ value not originally at the origin and each revalued sampled IQ value,
wherein a direction of rotation used to form each next revalued sampled IQ value is determined according to a correction look-up table that includes a set of correction values, and if the correction look-up table includes a positive value corresponding to the origin, then the direction of rotation is clockwise.
21. A method comprising:
a. sampling an input signal to generate a plurality of discrete sampled IQ values within an IQ domain, wherein each sampled IQ value includes an in-phase component and a quadrature component;
b. for a first sampled IQ value at the origin, revaluing the first sampled IQ value to a first revalued sampled IQ value, wherein the first revalued sample IQ value is a non-origin IQ value;
c. for each consecutive sampled IQ value at the origin that immediately follows the first sampled IQ value, rotating the first revalued sampled IQ value about the origin, thereby forming a next revalued sampled IQ value such that each next revalued sampled IQ value is an immediately preceding revalued sample IQ value rotated about the origin; and
d. modulating each sampled IQ value not originally at the origin and each revalued sampled IQ value,
wherein a direction of rotation used to form each next revalued sampled IQ value is dynamically determined according to a direction of rotation of an IQ trajectory immediately preceding the consecutively sampled IQ values at the origin.