Spread Spectrum Receiver Nonlinear Filtering for Non-Gaussian Interference
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Solution Overview
Problem
Existing spread spectrum receivers face challenges in effectively mitigating strong non-Gaussian interference, particularly due to the impracticality of optimal non-linearities and high complexity in implementing robust interference mitigation methods.
Innovation Solution
A method combining robust and adaptive non-linear processing with interference analyzers and pdf shaping filters to modify interference distributions, allowing for efficient mitigation in spatial, frequency, and other domains, suitable for various receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optimal non-linear processing is used for interference mitigation, then interference mitigation performance is improved, but device complexity becomes impractical
Solution Approach 1:
The patent transforms the optimal non-linear processing function from the time domain to the frequency domain using Fourier transforms. By operating on the spectral components rather than time-domain samples, the complexity is reduced while maintaining near-optimal interference mitigation performance. The frequency-domain representation allows for more efficient computation of the non-linear transformation.
Solution Approach 2:
The patent replaces direct time-domain non-linear processing with a frequency-domain based approach using Fourier transforms and spectral analysis. This substitution changes the computational mechanism from direct sample-wise non-linear operations to frequency-based transformations, reducing the practical implementation complexity while preserving the essential interference mitigation function.
2Reliability
If robust interference mitigation methods are implemented, then interference mitigation performance is improved, but device complexity increases
Solution Approach 1:
The patent employs probability distribution function (PDF) shaping filters that modify the statistical characteristics of the interference signal. By transforming the interference PDF to match desired statistical properties, the system achieves robust interference mitigation through parameter transformation rather than complex processing algorithms. This approach simplifies implementation while maintaining effectiveness against non-Gaussian interference.
3Reliability
If non-linear processing is applied to mitigate non-Gaussian interference, then interference mitigation is improved, but output dynamic range increases
Solution Approach 1:
The patent uses PDF shaping filters to transform the statistical distribution of the interference signal. By controlling the output PDF characteristics, the system manages the dynamic range of the processed signal. The frequency-domain non-linear processing also helps control dynamic range expansion by operating on spectral components rather than time-domain amplitudes directly.
Data Source
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AI summary
Systems, devices, methods, and computer-readable media for spread spectrum (SS) receiver interference mitigation are presented. An interference mitigation unit can include an interference analyzer that receives a complex-valued signal and estimates statistical characteristics of at least a portion of the complex-valued signal, a unit controller that receives the estimated statistical characteristics from the interference analyzer, classifies the interference distribution based on statistical characteristics as a Gaussian, long-tail, or short-tail, selects a non-linearity for that distribution, and a programmable non-linear module that performs a non-linear functional conversion of an envelope of the received complex-valued signal using a non-linear input-output characteristic based on the classification by the unit controller.