Sparse Antenna Array Beamforming for Small Communication Beams
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Solution Overview
Problem
Existing beamforming techniques in satellite communications are limited by the resolution of antenna arrays, resulting in large coverage areas and challenges in frequency reuse, particularly in satellite systems with geosynchronous earth orbits.
Innovation Solution
The use of large, sparse antenna arrays with unevenly distributed antennas and varying inter-element spacing, combined with beam coefficients, to form small communication beams with precise coverage areas and enable efficient frequency reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional antenna arrays are used in satellite communications, then the system structure is simple, but the beamforming resolution is low resulting in large coverage areas
Solution Approach 1:
The antenna array is segmented into multiple subarrays with different inter-element spacings. Each subarray can be independently controlled to form beams with different resolutions, allowing the system to achieve high beamforming resolution by combining signals from subarrays with varying spacing configurations.
Solution Approach 2:
Different regions of the antenna array have different inter-element spacings, creating local variations in beamforming characteristics. This allows certain subarrays to provide high-resolution focusing for specific directional ranges while maintaining overall system simplicity through modular subarray design.
2Productivity
If large coverage areas are used, then the antenna array structure is simple, but frequency reuse is difficult
Solution Approach 1:
The system dynamically adjusts beam coverage areas by selectively activating different subarrays with varying inter-element spacings. This allows the coverage area to be reduced for frequency reuse applications when needed, while maintaining the capability for larger coverage areas when simpler structures are sufficient.
3Measurement precision
If inter-element spacing is uniform, then the antenna array is easy to manufacture, but the beamforming resolution is limited
Solution Approach 1:
The antenna array is divided into multiple subarrays, each with uniform inter-element spacing that is easy to manufacture. The different subarrays have different spacing values, and their combined output achieves high beamforming resolution without requiring the entire array to have non-uniform spacing, thus maintaining manufacturing simplicity.
4Measurement precision
If more antennas are used, then the beamforming resolution increases, but the system complexity and cost increase
Solution Approach 1:
Instead of uniformly increasing the number of antennas across the entire array, the invention applies different inter-element spacings to different subarrays. This allows high beamforming resolution to be achieved in specific directional ranges using fewer antennas, reducing overall system complexity while maintaining the necessary resolution for frequency reuse.
Data Source
AI summary
An antenna array may be associated with forming discovery beams within a geographic area, where each discovery beam may be formed by a corresponding set of antennas of the antenna array and cover a discovery area within the geographic area. Preambles transmitted from terminals within a discovery area of a discovery beam may be detected using the antenna array. Based on detecting a preamble using a discovery beam, a presence of a terminal in a corresponding discovery area may be determined. Based on determining the presence of the terminal, signals detected at a second set of antennas of the antenna array may be processed according to beam coefficients to obtain a beam signal of a communication beam that includes a beam coverage area encompassing a position of the terminal. Each detected signal may comprise a respective component of a signal transmitted by the terminal.