Spectral Domain Beamforming for Reduced Computational Load
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Solution Overview
Problem
Current beamforming systems face challenges in efficiently forming broadband beams due to the complexity of achieving precise delays and equalizing reception channels, especially when dealing with broadband and multimode signals, which requires significant computational resources and leads to long temporal responses in filters, making them resource-intensive and inaccurate.
Innovation Solution
The method involves transforming signals into the spectral domain, using FIR architectures working in the frequency domain to generate and equalize beams, which reduces computational resources and improves accuracy by employing discrete Fourier transforms and inverse discrete Fourier transforms, allowing for efficient delay introduction and weighting, and multiplexing of beams to optimize resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If true time delay is used for broadband beamforming, then beamforming accuracy is improved, but device complexity and computational resources increase significantly
Solution Approach 1:
The patent replaces the mechanical approach of true time delay (physical delay lines) with a digital signal processing approach using phase shift in the frequency domain. Instead of physically delaying signals across broadband frequencies, the invention uses Fast Fourier Transform to convert signals to frequency domain, applies phase shifts, and transforms back, achieving equivalent beamforming with reduced hardware complexity.
Solution Approach 2:
The patent changes the parameter domain from time domain (true time delay) to frequency domain (phase shift). By operating in the frequency domain, the system achieves broadband beamforming capability with simpler computational operations. The phase shift parameter φ = 2πf0τ replaces the complex time-varying delay requirement, simplifying the beamforming operation while maintaining accuracy.
2Measurement precision
If FIR filters with long time response are used for channel equalization, then equalization precision is improved, but processing time and computational resources increase
Solution Approach 1:
The patent uses block-based processing with periodic Fast Fourier Transform operations to equalize channels. Instead of using long continuous FIR filters that require extensive processing time, the system processes signals in blocks, transforming to frequency domain where equalization becomes simple multiplication, then transforming back. This periodic block processing achieves high precision with reduced processing time.
Solution Approach 2:
The patent replaces the time-domain FIR filtering mechanism with frequency-domain multiplication. Channel equalization that would require long temporal convolution in the time domain is instead achieved through simple multiplicative operations in the frequency domain using FFT, dramatically reducing computational complexity and processing time while maintaining equalization precision.
3Adaptability or versatility
If sampling frequency is increased to cover largest bandwidth, then bandwidth coverage is improved, but data rate and processing load increase for narrowband modes
Solution Approach 1:
The patent implements dynamic sampling rate adaptation where the sampling frequency is adjusted according to the operational mode. For narrowband modes, the system uses a lower sampling rate to reduce processing load, while for broadband modes it switches to a higher sampling rate to ensure adequate bandwidth coverage. This dynamic adjustment optimizes the trade-off between bandwidth coverage and processing efficiency.
Solution Approach 2:
The patent changes the sampling frequency parameter based on the active operational mode. By dynamically modifying this fundamental system parameter, the architecture achieves adaptability across different bandwidth requirements without permanently maintaining the high processing load associated with the maximum sampling rate, thus optimizing productivity for each specific mode.
Data Source
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AI summary
The present invention relates to a method for forming Q beams by a computer of a beamforming system comprising P receiving channels each suitable for receiving signals from a respective antenna, the method comprising: - passing signals from each antenna into the spectral domain, - implementing operations in the spectral domain, the operations including pointing operations, the pointing operations comprising: - for each receiving channel, a generation operation by duplication of a contribution to each of the Q beams to be generated, - implementing for each contribution an operation of introducing a delay, and - an operation of summing the contributions to a beam to be generated from all the receiving channels, the summation operation being carried out for each beam to be generated.