Smart antenna arrays

• US 20020187813A1
• Filed: 05/23/2002
• Published: 12/12/2002
• Est. Priority Date: 06/12/2001
• Status: Active Grant

• Current Assignee: Mobisphere Ltd. (Siemens AG)
• Original Assignee: Mobisphere Ltd. (Siemens AG)
• Inventors: Guo, Yingjie Jay
• Granted Patent: US 7,079,868 B2
• Time in Patent Office: Days
• US Class Current: 455/562.1
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/0684 using different training sequences per antenna

Abstract

Improvements in or relating to Smart Antenna Arrays The present invention relates to a beamforming method for smart antenna arrays. Smart antennas employ arrays of low gain antennas connected to a combining/beamforming network. Smart antennas can provide enhanced coverage through range extension, hole filling and improved building penetration. By improving transmission and reception at the base station, the tolerable path losses can be increased whereby the range of the base station can be improved. A first aspect of the invention addresses the feedback signalling technique presently being considered by standards bodies for four antennas in large arrays. The invention is suitable for CDMA wireless cellular systems, as presently determined for third generation cellular wireless networks, and other wireless systems such as TDMA systems and wireless LANs.

Claims

1. A smart antenna basestation arrangement comprising an array of antenna elements, subdivided into a number of sub-arrays wherein:

an element or selected elements from each sub-array is operable to transmit pilot signals, which are, in operation, returned by mobile terminals in the area of coverage of the basestation;

the arrangement being operable to apply stored weight data and direction of arrival data together with feedback data to enable the array to generate directional downlink beams in the direction of said mobile.

2. An arrangement according to claim 1 wherein the feedback signal assists in the optimisation of phase and amplitude components for the beamforming weights to be assigned for dedicated channels.

3. An arrangement according to claim 1 wherein the feedback signal assists in the optimisation of a phase component for the beamforming weights to be assigned for dedicated channels.

4. An arrangement according to claim 1 wherein the feedback signal assists in the optimisation of an amplitude component for the beamforming weights to be assigned for dedicated channels.

5. An arrangement according to claim 3 wherein the phase information of the feedback signal is used to determine a phase component of the pilot antenna weights.

6. An arrangement according to claim 8 wherein the magnitude of the feedback signal is used to determine a magnitude component of the pilot antenna weights.

7. An arrangement according to claim 1 wherein the array has a physical periodicity whereby to reduce the number of principle optimum weight sets.

8. An arrangement according to anyone of claims 1-7 wherein the array comprises a circular array with a regular space between adjacent elements.

9. An arrangement according to anyone of claims 1-7 wherein the array comprises a square array.

10. An arrangement according to anyone of claims 1-7 wherein the antennas comprise directional antennas.

11. An arrangement according to anyone of claims 1-7 wherein the antennas comprise omni-directional antennas.

12. An arrangement according to any one of claims 1 to 3 wherein a number of angular directions are selected within an angle formed by two adjacent elements whereby to obtain the basic optimum weight set group.

14. A method according to claim 13 wherein the feedback signal assists in the optimisation of phase and amplitude components for the beamforming weights to be assigned for dedicated channels.

15. A method according to claim 13 wherein the feedback signal assists in the optimisation of a phase component or the beamforming weights to be assigned for dedicated channels.

16. An arrangement according to claim 13 wherein the feedback signal assists in the optimisation of a amplitude component for the beamforming weights to be assigned for dedicated channels.

13. A method of operating a smart antenna basestation arrangement comprising an array of antenna elements, subdivided into a number of sub-arrays, the method comprising the steps of:

transmitting. from an element or selected elements of each sub-array pilot signals,

receiving feedback signals returned by mobile terminals in the area of coverage of the basestation;

the arrangement being operable to apply stored weight data and direction of arrival data together with feedback data to enable the array to generate directional downlink beams in the direction of said mobile.