Multi-Carrier Receiver Interference Detection via Subcarrier Error Power
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Solution Overview
Problem
Existing communication systems, such as digital TV broadcast and WLAN, face challenges in effectively detecting and mitigating interference signals due to the unknown bandwidth of interference signals and high false accept rates in current methods, which affect the signal-to-noise ratio and can result in the filtering out of desired signals.
Innovation Solution
A method and apparatus for a multi-carrier receiver that decomposes a multi-carrier modulated signal into subcarriers, equalizes a target subcarrier, and compares the error power with a predefined threshold associated with the minimum distance between constellation points to determine interference, allowing for precise identification and mitigation of interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a notch filter is used to combat interference, then the interference signal can be reduced, but the bandwidth of the notch filter is preset and cannot adapt to unknown interference bandwidth, resulting in incomplete interference removal
Solution Approach 1:
The patent divides the frequency spectrum into multiple subcarriers and processes each subcarrier independently. By segmenting the interference detection and filtering process at the subcarrier level, the system can adapt to interference of unknown bandwidth without requiring a preset notch filter bandwidth, thus resolving the contradiction between interference reduction and bandwidth adaptability.
Solution Approach 2:
The patent implements dynamic interference detection and filtering by continuously monitoring error power on each subcarrier and adapting the filtering action based on real-time interference presence. This dynamic approach allows the system to respond to interference of varying bandwidths, overcoming the static bandwidth limitation of traditional notch filters.
2Measurement precision
If subcarrier-by-subcarrier interference detection is performed using DFT or FFT, then interference can be detected on specific subcarriers, but false accept rate is high due to difficulty in determining the interference detection threshold
Solution Approach 1:
The patent employs feedback mechanisms where the error power calculated from equalized subcarriers is used to dynamically adjust interference detection decisions. By feeding back the actual error power measurements and comparing them against thresholds, the system reduces false accept rates while maintaining accurate interference detection, resolving the contradiction between measurement precision and reliability.
3Object-affected harmful factors
If a subcarrier is filtered out when interference is detected, then the interference signal is removed, but both the desired signal and interference signal are filtered out simultaneously, adversely affecting the desired signal
Solution Approach 1:
The patent applies local quality by performing interference filtering at the subcarrier level rather than affecting the entire signal band. By identifying and filtering only the specific subcarriers where interference is detected (based on error power thresholds), the system removes interference while preserving the desired signal on non-affected subcarriers, thus resolving the contradiction between interference removal and desired signal preservation.
Data Source
AI summary
An interference processing method comprises: receiving a multi-carrier modulated signal, wherein the multi-carrier modulated signal comprises multi-carrier modulation symbols; discomposing the multi-carrier modulation symbols into a set of subcarriers, wherein the set of subcarriers at least comprises a target subcarrier; equalizing the target subcarrier to obtain an equalized target subcarrier; obtaining an error power of the equalized target subcarrier; and comparing the error power of the equalized target subcarrier with a predefined threshold to determine the existence of interference in the target subcarrier, wherein the predefined threshold is associated with a minimum distance between two constellation points of a modulation constellation of the target subcarrier.