Smart antenna arrays
First Claim
1. A smart antenna basestation arrangement comprising a 2-dimensional array of antenna elements wherein:
- the antenna array provides omnidirectional beam coverage in a two dimensional azimuth plane, and stored beamforming weight sets optimised for specific beam directions are operable to enable the array to generate directional downlink beams in the azimuth plane; and
the array has a physical periodicity whereby to reduce the number of principal weight sets for specific beam directions and whereby secondary weight sets are obtained by rotation.
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Accused Products
Abstract
The present invention relates to a beamforming method for smart antenna arrays, and in particular relates to a beamforming method for smart two-dimensional antennas. 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 thus provides a method of generating low sidelobe beampatterns for 2-dimensional arrays. A further aspect addresses the feedback signalling techniques which are presently being considered by standard 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.
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Citations
16 Claims
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1. A smart antenna basestation arrangement comprising a 2-dimensional array of antenna elements wherein:
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the antenna array provides omnidirectional beam coverage in a two dimensional azimuth plane, and stored beamforming weight sets optimised for specific beam directions are operable to enable the array to generate directional downlink beams in the azimuth plane; and
the array has a physical periodicity whereby to reduce the number of principal weight sets for specific beam directions and whereby secondary weight sets are obtained by rotation. - View Dependent Claims (2, 3, 4, 5)
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6. A smart antenna basestation arrangement comprising a two-dimensional array of antenna elements, wherein:
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the antenna array provides omnidirectional beam coverage in a two dimensional azimuth plane;
the antenna elements are subdivided into a plurality of sub-arrays;
stored beamforming weight sets optimized for specific beam directions are operable to enable the array to generate directional downlink beams in the azimuth plane; and
a pilot antenna element from each sub-array is operable to broadcast common control channel signals, the array being operable to receive any 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 range data to enable the array to generate directional downlink beams in the direction of said mobile terminal. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A method of operating a smart antenna basestation arrangement comprising a 2-dimensional array in an azimuth plane of antennas comprising the steps of:
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storing beamforming weight sets optimized for specific beam directions whereby to enable the array to generate directional downlink beams; and
obtaining secondary weight sets by rotation whereby to reduce the number of principal weight sets for specific beam directions;
wherein,the antenna array provides omnidirectional beam coverage in a two-dimensional azimuth plane; and
the array has a physical periodicity. - View Dependent Claims (15, 16)
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Specification