MULTI-FINGER BEAMFORMING AND ARRAY PATTERN SYNTHESIS

• US 20180331740A1
• Filed: 05/11/2017
• Published: 11/15/2018
• Est. Priority Date: 05/11/2017
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: ORHAN, Oner, SASOGLU, Eren, NIKOPOUR, Hosein, TALWAR, Shilpa
• Granted Patent: US 10,334,454 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 17/102 Power radiated at antenna
• CPC Class Codes: H04B 17/327 Received signal code power [RSCP]
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

A communication device includes an antenna array, and a beamforming controller configured to determine a set of beamforming weights for the antenna array based on a target radiation pattern having a plurality of main fingers, wherein the beamforming controller is configured to, in each of a plurality of iterations identify a search space of beamforming weights for a plurality of elements of the antenna array, and determine, based on contribution of one or more of the plurality of elements of to multiple of the plurality of main fingers, an updated set of beamforming weights in the search space to reduce a difference between an actual radiation pattern and the target radiation pattern, the antenna array configured to transmit or receive radio signals based on the updated set of beamforming weights.

Claims

1. A communication device comprising:

an antenna array; and

a beamforming controller configured to;

determine a set of beamforming weights for the antenna array based on a target radiation pattern having target main finger power levels for a plurality of main fingers and a target maximum sidelobe power level, wherein the beamforming controller is configured to determine the set of beamforming weights by, in each of a plurality of iterations;

identifying a search space of beamforming weights for a plurality of elements of the antenna array, and

updating based on actual main finger power levels and actual sidelobe power levels of the set of beamforming weights, the set of beamforming weights within the search space to reduce a difference between actual main finger power levels and the target main finger power levels and to reduce the actual sidelobe power levels toward or below the target maximum sidelobe power level;

the antenna array configured to transmit or receive radio signals based on the set of beamforming weights.

2. The communication device of claim 1, wherein the beamforming controller comprises one or more processors configured to execute program code or as digitally-configured hardware circuitry.

3. The communication device of claim 1, wherein the beamforming controller is configured to update the set of beamforming weights by determining the actual main finger power levels and the actual sidelobe power levels based on current values of the set of beamforming weights for a current iteration.

4. The communication device of claim 1, wherein the beamforming controller is configured to update the set of beamforming weights within the search space by updating the set of beamforming weights based on a least-squares problem that attempts to minimize a difference between the target radiation pattern and an actual radiation pattern comprising the actual main finger power levels and the actual sidelobe power levels.

5. The communication device of claim 1, wherein the set of beamforming weights are phase-only beamforming weights located on the unit circle.

6. The communication device of claim 1, wherein, for a first element of the plurality of elements of the antenna array, the search space for the beamforming weight is a tangent line of the unit circle at the beamforming weight of the first element of the plurality of elements of the antenna array, and wherein the beamforming controller is configured to update the set of beamforming weights within the search space by:

determining a solution to a least-squares problem along the tangent line for the first element of the plurality of elements of the antenna array;

locating a closest point on the unit circle to the solution on the tangent line for the first element of the plurality of elements of the antenna array; and

updating the beamforming weight for the first element of the plurality of elements of the antenna array to be the closest point on the unit circle.

7. The communication device of claim 1, wherein the beamforming controller is configured to update the set of beamforming weights for the antenna array by:

iteratively identifying the search space and updating the set of beamforming weights until the set of beamforming weights satisfies a convergence condition.

8. The communication device of claim 7, wherein the beamforming controller is further configured to:

after the set of beamforming weights satisfies the convergence condition, update a maximum main finger power level or update the target maximum sidelobe power level based on the actual main finger power levels and the actual sidelobe power levels; and

iteratively re-determine the set of beamforming weights for the antenna array by identifying the search space and updating the set of beamforming weights based on the maximum main finger power level and the target maximum sidelobe power level.

9. A communication device for synthesis of radiation patterns for antenna arrays, the communication device comprising:

an antenna array; and

a beamforming controller configured to;

determine a set of beamforming weights for an antenna array based on a target radiation pattern by, for each of a plurality of iterations;

identifying a search space for beamforming weights for a plurality of elements of the antenna array, and

updating the set of beamforming weights within the search space based on reducing a difference between an actual radiation pattern and the target radiation pattern at a first set of angles and further based on maintaining power levels of the actual radiation pattern below upper-bound power levels of the target radiation pattern at a second set of angles.

the antenna array configured to transmit or receive radio signals based on the set of beamforming weights.

10. The communication device of claim 9, wherein updating the set of beamforming weights comprises determining the actual radiation pattern based on current values of the set of beamforming weights for a current iteration.

11. The communication device of claim 9, wherein the target radiation pattern is defined over one or more main finger angles and one or more sidelobe angles.

12. The communication device of claim 11, wherein the beamforming controller is further configured to, in each iteration:

determine if the actual radiation pattern at any of the one or more sidelobe angles in the first set of angles is below one of the upper-bound power levels, and assign the identified sidelobe angles to the second set of angles if the actual radiation pattern is below the upper-bound power level.

13. The communication device of claim 9, wherein the beamforming controller is configured to update the set of beamforming weights by:

determining a solution for least-squares problem for the first set of angles that reduces the difference between the actual radiation pattern and the target radiation pattern while constraining the set of beamforming weights to keep the actual radiation pattern below the upper-bound power levels at the second set of angles.

15. The communication device of claim 9, wherein the beamforming controller is configured to determine the set of beamforming weights for the antenna array by:

iteratively identifying the search space and updating the set of beamforming weights until the set of beamforming weights satisfies a convergence condition.

16. The communication device of claim 9, wherein the set of beamforming weights are for phase-only beamforming and wherein the search space constrains the set of beamforming weights to locations on the unit circle.

17. The communication device of claim 9, wherein, for a first element of the plurality of elements of the antenna array, the search space for the beamforming weight is a tangent line of the unit circle at a current value of the beamforming weight of the first element of the plurality of elements of the antenna array, and wherein the beamforming controller is configured to solve for the set of beamforming weights within the search space by:

determining a solution to a least-squares problem for the first set of angles along the tangent line for the first element;

locating a closest point on the unit circle to the solution on the tangent line for the first element of the plurality of elements of the antenna array; and

using the closest point on the unit circle as the beamforming weight for the first element of the plurality of elements of the antenna array in the set of beamforming weights.

18. The communication device of claim 9, wherein the set of beamforming weights are for phase control with amplitude tapering beamforming and wherein the search space constrains the set of beamforming weights locations within a two-dimensional ring comprising radial distances between a minimum tapering amplitude and the unit circle.

19. The communication device of claim 9, wherein, for a first element of the plurality of elements of the antenna array, the search space for the beamforming weight is a region between the unit circle and a line intersecting the unit circle that is perpendicular to the line between the origin of the unit circle and a current value of the beamforming weight, and wherein the beamforming controller is configured to update the set of beamforming weights within the search space by updating the set of beamforming weights in the region.

20. The communication device of claim 9, wherein the set of beamforming weights are phase and amplitude control beamforming and wherein the search space constrains the set of beamforming weights locations within the unit circle.

14. (canceled)

21. A method of performing beamforming, the method comprising:

determining, based on a target radiation pattern having target main finger power levels for a plurality of main fingers and a target maximum sidelobe power level, a set of beamforming weights for an antenna array by performing a plurality of iterations of;

identifying a search space of beamforming weights for a plurality of elements of the antenna array, and

updating, based on actual main finger power levels and actual sidelobe power levels of a current set of beamforming weights, the set of beamforming weights within the search space to reduce a difference between the actual main finger power levels and the target main finger power levels and to reduce the actual sidelobe power levels toward or below the target maximum sidelobe power level;

the method further comprising transmitting or receiving radio signals with the antenna array based on the set of beamforming weights.

22. The method of claim 21, wherein updating the set of beamforming weights comprises determining the actual main finger power levels and the actual sidelobe power levels based on current values of the set of beamforming weights for a current iteration.