Interference Cancellation Repeater for Stable LTE Signal Amplification
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Solution Overview
Problem
In mobile communication systems, interference cancellation repeaters face instability due to sudden changes in signal levels, particularly with LTE signals, leading to oscillation issues when amplification gain is not properly set.
Innovation Solution
An interference cancellation repeater is designed with a sync signal detector to accurately measure sync signal levels before and after feedback cancellation, and a gain controller adjusts the signal amplifier based on the difference between these levels to maintain stable amplification, using components like low-pass filters and level detectors to calculate power levels and ensure appropriate amplification gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If amplification gain is increased to improve signal strength, then signal coverage is improved, but oscillation occurs due to feedback signal amplification
Solution Approach 1:
The patent detects the feedback signal that causes oscillation and converts it into a useful component for cancellation. By identifying the feedback signal characteristics and subtracting it from the input signal, the system transforms the harmful oscillation source into a beneficial cancellation mechanism, allowing higher amplification gain without oscillation.
Solution Approach 2:
The patent implements a feedback cancellation mechanism where the output signal is monitored, the feedback portion is identified, and this feedback information is used to adjust the amplification process. The feedback signal detection and cancellation loop enables the system to maintain stability while operating at higher gain levels by continuously compensating for feedback effects.
2Stability of the object's composition
If amplification gain is decreased to prevent oscillation, then system stability is improved, but signal coverage deteriorates
Solution Approach 1:
The feedback signal that causes stability issues is converted into a useful cancellation component. By detecting and subtracting the feedback signal from the input signal before amplification, the system eliminates the harmful oscillation effect while preserving the ability to amplify the desired signal at higher gain levels, thus improving both stability and signal strength simultaneously.
3Adaptability or versatility
If amplification gain is dynamically adjusted to adapt to signal level changes, then adaptability is improved, but device complexity increases
Solution Approach 1:
The system performs self-adjustment by automatically detecting the feedback signal characteristics and calculating the appropriate cancellation amount. The feedback cancellation mechanism operates autonomously without requiring external control inputs, dynamically adapting to changing signal conditions while maintaining relatively simple device architecture through self-service operation.
4Stability of the object's composition
If feedback signal cancellation is implemented to prevent oscillation, then system stability is improved, but device complexity increases
Solution Approach 1:
The patent converts the harmful feedback signal into a useful cancellation component by detecting it and subtracting it from the input signal. This approach achieves oscillation prevention through a relatively simple subtraction operation rather than requiring complex active cancellation mechanisms, thus improving stability while minimizing the increase in device complexity.
Data Source
AI summary
According to an aspect of the inventive concept, there is provided an interference cancellation repeater for repeating a long term evolution (LTE) signal between a terminal and a base station, the interference cancellation repeater includes: an interference canceller configured to generate a restored LTE signal by canceling a feedback signal included in an input LTE signal; a sync signal detector configured to detect a first sync level which is a level with respect to a sync signal of the input LTE signal and a second sync level which is a level with respect to a sync signal of the restored LTE signal; and a gain controller configured to control a signal amplifier according to isolation calculated based on a difference between the first sync level and the second sync level.