WLAN Access Point Interference Suppression via Spatial Filtering
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Solution Overview
Problem
Wireless local area networks (WLANs) operating in license-exempt bands face interference issues due to unpredictable and varying interference environments, which affect data transmission rates and network performance.
Innovation Solution
The implementation of a dynamic interference handling (DIH) processor and interference suppression spatial filter (ISSF) using multiple antennas at the access point to analyze and mitigate interference by adjusting receive gains, detection thresholds, and calculating filter coefficients to null out interference, thereby enhancing network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple antennas are used for signal reception, then signal diversity and interference mitigation capability are improved, but device complexity increases
Solution Approach 1:
The patent segments the received signal into multiple independent antenna channels, processing each channel separately through correlation detection and interference analysis, then combines the results for comprehensive interference mitigation while maintaining manageable processing complexity
Solution Approach 2:
The patent introduces an intermediary processing stage that analyzes correlation between antenna signals to detect interference patterns, acting as a mediator that identifies harmful signals before they affect the final reception decision
2Object-affected harmful factors
If interference suppression spatial filter is applied, then interference mitigation is improved, but false alarm rate increases due to dynamic interference characteristics
Solution Approach 1:
The patent implements feedback mechanisms where the system continuously monitors the effectiveness of interference suppression, adjusts spatial filter parameters based on detected interference patterns, and validates results to minimize false alarms while maintaining suppression effectiveness
Solution Approach 2:
The patent dynamically changes parameters of the spatial filter based on the detected interference characteristics, adjusting filter coefficients and thresholds to adapt to varying interference conditions while maintaining optimal performance
3Measurement precision
If receive gain is increased to improve signal sensitivity, then detection capability is improved, but interference impact is also amplified
Solution Approach 1:
The patent applies different receive gain levels to different antenna channels based on their individual signal and interference characteristics, optimizing sensitivity for each channel while preventing interference amplification through localized gain control
Data Source
AI summary
A wireless access point coherently receives signals transmitted from client devices and from interfering devices, measures noise and interference capture samples from the received signals, and computes a characterization of noise plus interference. Receive gains and threshold levels are adjusted based on the computed noise plus interference characterization. A set of weights for an interference suppression spatial filter are calculated from the measured noise and interference capture samples and used to produce a filtered signal by spatially filtering the received signals such that interference is spatially nulled in the filtered signal. The method may also include setting PHY parameters at the wireless access point based on the computed noise plus interference characterization. In some embodiments, a protection transmission is transmitted from the wireless access point, requesting connected client devices to suspend transmissions during a specified time period.