Frequency Domain Windowing for Narrow-Band Interference Suppression
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Solution Overview
Problem
Narrow-band interference in spread spectrum communication systems causes degradation in system performance, increased congestion, call-dropping rates, and power consumption, especially due to the limitations of analog and digital filtering methods which struggle with adaptability and spectrum leakage.
Innovation Solution
A method and device using windowing in the frequency domain to identify and suppress narrow-band interference by extracting sampling points, computing energy accumulation, determining interference locations and widths, and adjusting window shapes to minimize spectrum leakage, thereby enhancing interference suppression capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frequency domain filtering is used to eliminate narrow-band interference, then interference suppression capability is improved, but spectrum leakage occurs causing adjacent frequency points to be affected
Solution Approach 1:
The patent applies windowing functions with different characteristics to different frequency regions. Specifically, it uses rectangular windows for strong interference signals, Hanning windows for typical interference signals, and Blackman windows for weak interference signals. This localized adaptation of window characteristics to different interference conditions effectively suppresses spectrum leakage while maintaining interference suppression capability.
Solution Approach 2:
The patent dynamically changes the window function parameter (type of window) based on the interference signal strength. By detecting the interference level and selecting appropriate window functions (rectangular, Hanning, or Blackman), the system optimizes the balance between interference suppression and spectrum leakage mitigation for each specific condition.
2Object-affected harmful factors
If analog notch filtering is used to suppress narrow-band interference, then interference elimination is improved, but system flexibility and adaptability deteriorate
Solution Approach 1:
The patent implements a dynamic interference suppression system that automatically detects narrow-band interference characteristics and adapts the windowing parameters in real-time. The system continuously monitors the frequency spectrum, identifies interference signals, and adjusts the window function selection and parameters dynamically, providing both effective interference elimination and high system flexibility.
Solution Approach 2:
The system performs self-adjustment by automatically detecting interference signals and selecting appropriate windowing strategies without external intervention. The interference suppression unit autonomously analyzes the frequency spectrum, identifies narrow-band interference, and applies the suitable window function, making the system self-adaptive and flexible.
3Object-affected harmful factors
If frequency domain processing is applied to all data points, then interference suppression is improved, but computational complexity and processing time increase
Solution Approach 1:
The patent applies frequency domain windowing processing selectively rather than uniformly to all data points. By identifying specific frequency regions containing narrow-band interference and applying windowing only to those regions, the system achieves effective interference suppression while minimizing the computational burden and processing time compared to processing the entire spectrum.
Data Source
AI summary
A device and method for eliminating narrow-band interference by windowing in a spread spectrum system are disclosed. The method comprises extracting N sampling points of data to perform frequency spectrum transform each time and obtaining N points of data; updating control information, comparing the energy values of the N points with the threshold within the set time period to determine the number of narrow-band interference as well as the width and location of the interference; determining the corresponding frequency domain adjusting window based on the width and location of the narrow band interference, obtaining the points within the window and the adjusted values of those points; with regard to the transformed N points during interference elimination process, setting the energy values of the points within the window during the current time period and the last period as the corresponding adjusted values, outputting the points after frequency spectrum inverse transform.