Wireless Device Frequency Selection Avoiding Harmonic Distortion
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Solution Overview
Problem
Wireless network devices experience degradation due to harmonic distortion and inter-modulation distortion from cellular signals, particularly second or third order distortions, which interfere with their operating channels, especially in close proximity to cellular signal sources like DAS or base stations, affecting RF link quality.
Innovation Solution
A wireless device equipped with a monitor and processor to detect cellular signals, calculate interference frequencies, estimate energy levels, and determine available frequencies to avoid transmission in bands affected by second or third order harmonic and inter-modulation distortions, thereby selecting operating channels that minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If wireless network devices operate close to cellular signal sources, then coverage and signal strength are improved, but harmonic distortion and inter-modulation distortion from cellular signals interfere with WLAN operating channels, degrading link quality
Solution Approach 1:
The system performs preliminary detection of cellular signals and calculates potential interference frequencies (harmonic and inter-modulation distortion) before WLAN transmission. By identifying problematic frequency bands in advance, the system can pre-select clean channels and avoid transmitting on frequencies that would be affected by distortion, thus preventing interference before it degrades link quality
Solution Approach 2:
The system applies different quality control to different frequency bands by selectively avoiding specific channels that are susceptible to interference while allowing transmission on clean channels. Instead of uniformly reducing power across all frequencies, the system maintains high signal strength on unaffected channels while suppressing transmission only on channels where harmonic distortion and inter-modulation distortion would occur
2Reliability
If the wireless device skips frequency bands with high interference levels, then link quality is improved, but available transmission channels are reduced
Solution Approach 1:
The system segments the frequency spectrum into multiple individual channels and evaluates each channel's susceptibility to interference separately. By calculating harmonic and inter-modulation distortion frequencies based on detected cellular signals, the system identifies specific contaminated channels while leaving clean channels available for transmission. This segmentation allows selective channel avoidance rather than blanket frequency band rejection, maintaining productivity on unaffected channels
3Reliability
If the wireless device detects and calculates interference frequencies from cellular signals, then transmission on clean channels is ensured, but device complexity and processing requirements increase
Solution Approach 1:
The wireless device performs self-detection of cellular signals and self-calculation of potential interference frequencies using its own processing capabilities. The device autonomously identifies harmonic and inter-modulation distortion frequencies based on detected cellular signals and automatically adjusts its transmission channel selection accordingly, without requiring external assistance or complex additional hardware
Data Source
AI summary
An example device comprising: a monitor to detect cellular signals; and a processor to: calculate frequencies of interferences produced due to the detected cellular signals; estimate energy levels of the interferences at the calculated frequencies; and determine available frequencies based on the calculated frequencies and the estimated energy levels to avoid transmissions on a plurality of frequency bands associated with a second order harmonic distortion, a third order harmonic distortion, a second order inter-modulation distortion (IMD 2), or a third order inter-modulation distortion (IMD 3).