Phased-Array Antenna Interference Suppression via Subband Power
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Solution Overview
Problem
Phased-array antenna systems face challenges in efficiently suppressing interference due to the high cost and complexity of fully-adaptive algorithms, which require one receiver per antenna feed element and extensive calibration, limiting their feasibility for large arrays, especially when interferers are close to desired signals.
Innovation Solution
A system that combines the simplicity of weight-constrained iterative algorithms with the performance of fully-adaptive algorithms, using a genetic algorithm to calculate beam weights based on known geographic locations of user terminals, eliminating the need for element receivers and incorporating spatial constraints to suppress interference across all antenna feed elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fully-adaptive algorithms are employed to suppress interference, then interference suppression performance is improved, but device complexity and cost increase due to requiring one receiver per antenna feed element and extensive calibration
Solution Approach 1:
The patent extracts the interference suppression function from the signal reception function by using a separate wideband receiver to monitor interference sources. This allows the main antenna feed elements to focus on signal reception while the dedicated receiver handles interference characterization, eliminating the need for multiple receivers per element and reducing calibration requirements.
Solution Approach 2:
The patent introduces an intermediary processing stage that uses measured power levels across frequency subbands to identify interference sources. This intermediary analysis layer enables the system to suppress interference without requiring fully-adaptive algorithms at each antenna element, thereby reducing complexity while maintaining effectiveness.
2Device complexity
If weight-constrained iterative algorithms are used to eliminate element receivers, then device complexity is reduced, but interference suppression performance deteriorates when interferers are close to desired signals
Solution Approach 1:
The patent performs preliminary identification of interference sources by measuring power levels across frequency subbands before applying cancellation techniques. This preliminary action characterizes the interference in advance, allowing the system to target specific frequency ranges for suppression without requiring complex real-time adaptive processing, thus maintaining performance with reduced complexity.
Solution Approach 2:
The patent transitions from spatial domain processing to frequency domain processing by analyzing power levels across multiple frequency subbands. This dimensional shift enables the system to identify and suppress interference based on spectral characteristics rather than spatial constraints, improving performance near desired signals while using simpler algorithms.
3Measurement precision
If one receiver per antenna feed element is implemented, then measurement precision for signal determination is improved, but manufacturing cost increases dramatically
Solution Approach 1:
The patent implements a universal wideband receiver that serves multiple functions: characterizing interference sources, measuring power levels across frequency subbands, and providing data for cancellation pattern generation. This single multi-functional receiver replaces the need for multiple dedicated receivers, significantly reducing manufacturing cost while maintaining measurement precision through sophisticated signal processing.
Solution Approach 2:
The patent changes the operating parameters of the receiver system by using a wideband receiver that operates across the entire frequency range of interest. By measuring power levels across multiple frequency subbands and analyzing spectral characteristics, the system achieves accurate signal determination without requiring multiple narrowband receivers, thereby reducing cost while maintaining precision.
Data Source
AI summary
A phased-array antenna system includes an array of antenna feed elements that produces a radiation pattern to provide spot beams within which to receive a signal in a frequency band and carrying communication from a terminal at a known geographic location. A beamformer forms the spot beams; and a channelizer divides the frequency band into frequency subbands, and measures power levels of the signal over respective frequency subbands. And an antenna controller selects a frequency subband based on the measured power levels indicating that the signal includes an identifiable interference, and calculates a set of beam weights based on the measured power level over the selected frequency subband, and based on the known geographic location of the terminal. The beamformer, then, forms the spot beams based on the calculated set of beam weights to thereby suppress at least some of the identifiable interference from the signal.