Adaptive Pulse Suppression for OFDM Signal Interference

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Solution Overview

Problem

Existing methods for suppressing pulse-shaped interference in OFDM signals, such as pulse blanking, often impair the actual OFDM signal and require a fixed limit value that is not optimal due to changing signal-to-noise ratios and interference parameters during transmission.

Innovation Solution

A method that iteratively determines an adaptive limit value for pulse suppression by maximizing the signal-to-interference-and-noise ratio (SINR) based on residual interference power, useful signal power, and noise power, allowing for optimized pulse masking and minimizing bit error rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a fixed limit value is used for pulse suppression, then the implementation is simple, but the transmission performance is reduced due to changing signal-to-noise ratio and interference parameters

Engineering Contradiction:
Improvesimplicity of implementationVSAvoidtransmission performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies dynamics by transitioning from a fixed limit value to an adaptive limit value that changes based on current channel conditions. The receiver determines the limit value dynamically using feedback information about signal-to-noise ratio and interference characteristics, allowing the system to adapt to varying transmission conditions and maintain optimal performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by using information about the actual transmission conditions (signal-to-noise ratio, interference power) to adjust the limit value. The receiver measures these parameters and uses them to determine the optimal limit value for pulse suppression, creating a closed-loop system that continuously optimizes performance based on real-time conditions.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If the limit value is set high to suppress strong interference, then interference cancellation is improved, but the OFDM signal is severely impaired

Engineering Contradiction:
Improveinterference cancellationVSAvoidOFDM signal quality
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies parameter changes by adjusting the limit value based on measured signal-to-noise ratio and interference characteristics. Instead of using a fixed high threshold that always suppresses strongly, the limit value is adapted to the current conditions, allowing optimal balance between interference suppression and signal preservation in each transmission scenario.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by tailoring the suppression threshold to specific local conditions (signal-to-noise ratio, interference power) rather than using a uniform threshold. This allows the system to apply different suppression levels appropriate to each transmission condition, optimizing both interference cancellation and signal quality locally.

Inventive Principle:
Principle #3Local quality

3Reliability

If the limit value is set low to preserve the OFDM signal, then signal impairment is reduced, but interference suppression becomes insufficient

Engineering Contradiction:
ImproveOFDM signal qualityVSAvoidinterference suppression
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses parameter changes to adjust the limit value based on actual interference and signal conditions. When interference is strong and signal-to-noise ratio is high, the limit value is increased for stronger suppression. When conditions are poorer, the limit value is reduced to preserve signal quality, achieving optimal balance dynamically.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2720393B1Removal of pulse-shaped interferences in an OFDM signal
Publication Date: 2016.06.29 DEUTSCHES ZENTRUM FÜR LUFT UND RAUMFAHRT E V
  • EP2720393B1 patent drawingFigure 1
  • EP2720393B1 patent drawingFigure 2
  • EP2720393B1 patent drawingFigure 3

AI summary

The invention relates to a method and a device for suppressing pulse-shaped interference in an OFDM signal r received by a receiver.The receiver receives the OFDM signal r, with the following steps: Specifying (101) a limit value Tn with n = 1, silencing (102) signal components of the impulsive interference of the OFDM signal r whose signal amplitudes are greater than the limit value Tn, whereby after silencing the signal components the signal y(r,Tn) is present, determining (103) a residual interference power PL(y(r,Tn)) of the signal y(r,Tn), determining (104) a useful signal power PS(y(r,Tn)) of the signal y(r,Tn), determining (105) a noise power PN(y(r,Tn)) of the signal y(r,Tn), determining (106) a signal-to-interference-to-noise ratio SINR(y(r,Tn)), determining (107) an optimized limit value Tm for silencing the Impulsive interference of the OFDM signal r by repeatedly performing steps two to six, whereby the signal-to-interference-and-noise ratio SINR(Tn) is iteratively varied by varying the limit value Tn for n = 2, 3,..., m, is maximized, so that for Tm: SINR(y(r,Tm)) = Max(SINR(y(r,Tn)), and suppression (108) of the impulse interference of the OFDM signal r, whose signal amplitudes are greater than the limit Tm, where after suppression the signal y(r,Tm) is present.