Circular Antenna Array Codebook Design for Beam Steering
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Solution Overview
Problem
Conventional wireless communication systems using circular antenna arrays face limitations in beam steering, leading to reduced signal strength and lost communications due to the reliance on discrete Fourier transform (DFT) vectors, which are ineffective in steering beams to changing or arbitrary locations of user equipment (UE).
Innovation Solution
The implementation of non-DFT vectors for codebook design and feedback in circular antenna arrays, allowing for improved beamforming gain and throughput by enabling the transmitter circle array to steer beams to user equipment using codebooks, quantization rules, and signaling procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DFT vectors are used for beamforming in circular antenna arrays, then the system structure is simple and implementation is straightforward, but beam steering capability is limited and cannot effectively steer beams to arbitrary UE locations
Solution Approach 1:
The patent transforms the beamforming vectors from DFT domain to spatial domain by changing the parameter representation. Instead of using DFT vectors with fixed frequency domain parameters, the invention uses spatial domain vectors with parameters including azimuth angle, elevation angle, and 3D spatial coordinates. This parameter transformation enables continuous beam steering to arbitrary locations while maintaining codebook structure through systematic parameterization of beam directions.
Solution Approach 2:
The invention introduces dynamic beam steering capability by making the codebook vectors adaptive to UE location. The spatial domain codebook vectors are designed to dynamically adjust beam directions based on UE position, allowing the system to track and serve moving users. The codebook includes vectors that can be selected based on real-time spatial parameters, enabling dynamic adaptation to changing channel conditions and user locations.
2Reliability
If conventional DFT-based codebooks are used, then the implementation is straightforward, but signal strength is reduced and communications are lost at non-boresight locations
Solution Approach 1:
The patent changes the parameter domain from frequency (DFT) to spatial coordinates, enabling accurate beam steering to non-boresight locations. The spatial domain codebook uses parameters such as azimuth angle (phi), elevation angle (theta), and 3D spatial coordinates to precisely target beams at arbitrary UE locations. This parameter transformation maintains implementation feasibility through systematic codebook construction while dramatically improving signal strength and communication reliability at off-boresight positions.
3Productivity
If non-DFT vectors are implemented for beam steering, then beamforming gain and throughput are improved, but codebook design and feedback complexity increases
Solution Approach 1:
The invention implements dynamic codebook feedback where the UE reports spatial parameters (azimuth angle, elevation angle, or 3D coordinates) instead of traditional DFT-based PMI. This dynamic feedback mechanism enables the BS to select appropriate spatial domain codebook vectors that adapt to current channel conditions and UE location. The feedback complexity is managed through structured reporting of spatial parameters with defined precision levels, balancing throughput improvement with feasible feedback overhead.
Solution Approach 2:
The patent adds spatial dimensionality to the codebook design by introducing 3D spatial coordinates and angular parameters. This dimensional transformation from 1D frequency index to 3D spatial representation enables comprehensive beam steering capability. The codebook structure organizes vectors according to spatial dimensions, allowing efficient selection and feedback of spatial parameters while achieving superior beamforming gain and throughput performance.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described for closed-loop precoding for multiple-input multiple-output for transmitter circle arrays, for example uniform circular array panels. In some aspects, a base station including a transmitter circle array may steer a beam to a user equipment (UE) using codebooks, quantization rules, and feedback from the user equipment. In some aspects, the same transmitter circle array may be used for both backhaul communications with a device at a fixed location, for example using beams formed via discrete Fourier transform (DFT) vectors, and access communications with a UE via non-DFT beams coded using closed-loop precoding.