Receiver Attenuation Control for Broadband Interference Mitigation
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Solution Overview
Problem
Conventional radios, such as Land Mobile Radios, experience significant intermodulation interference when close to broadband sites, leading to degraded performance due to high noise floors caused by broadband signals with high peak to average power ratios.
Innovation Solution
A communication device continuously monitors multiple channels, estimates the noise floor, and adjusts the attenuation level using a variable attenuator to mitigate intermodulation interference by determining an optimal attenuation level based on incremental changes and slope comparisons, ensuring the receiver operates in a more linear region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a variable attenuator is added to mitigate intermodulation interference, then receiver sensitivity is improved, but device complexity increases
Solution Approach 1:
The system continuously monitors the noise floor level and uses this feedback to dynamically control the variable attenuator. The processor compares the measured noise floor against a threshold and adjusts the attenuation level accordingly, creating a closed-loop control system that adapts to changing interference conditions while maintaining receiver sensitivity.
Solution Approach 2:
The variable attenuator is controlled dynamically rather than being fixed, allowing the system to adapt its attenuation level in real-time based on the detected interference conditions. This dynamic adjustment enables the receiver to optimize performance across varying signal environments without requiring complex hardware modifications.
2Reliability
If attenuation is applied to reduce noise floor, then receiver performance is improved, but signal strength is reduced
Solution Approach 1:
The system applies partial attenuation only when and where needed, rather than using fixed maximum attenuation. By monitoring the noise floor and applying attenuation selectively based on detected interference levels, the system achieves sufficient noise reduction without excessively weakening desired signals, optimizing the balance between noise floor reduction and signal strength preservation.
Data Source
AI summary
Systems and methods for operating a communication device so as to mitigate intermodulation interference to a signal. The methods comprise: continuously monitoring several communication channels by the communication device; using a noise floor level estimate of the communication device to detect when the communication device is under an influence of hig interference; determining an optimal level of attenuation to be applied by a variable attenuator of the communication device's receiver so as to mitigate the influence of intermodulation interference to the signal; and selectively adjusting an amount of attenuation being applied by the variable attenuator to achieve the optimal level of attenuation for mitigating intermodulation interference.