Interference Cancellation Repeater Gain Control
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Solution Overview
Problem
Interference cancellation repeaters face challenges in maintaining stable gain levels and preventing oscillation due to rapid changes in signal intensity and isolation between antennas, leading to inadequate interference cancellation and limited output gain.
Innovation Solution
An interference cancellation repeater with a gain controller that detects gain changes and adjusts the current gain to a target level by modifying the intensity of RF input, interference-canceled, and RF output signals, using a combination of attenuators and amplifiers, allowing for gradual and controlled gain adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the gain level is changed immediately to a predetermined level, then the response speed is improved, but the interference cancellation capability deteriorates because the estimation cannot follow the gain change
Solution Approach 1:
The patent applies periodic action by implementing gradual gain adjustment through multiple stages or steps rather than immediate change. The gain controller adjusts the gain level incrementally over time, allowing the interference signal estimation to continuously track and adapt to each intermediate gain level, thereby maintaining reliable interference cancellation throughout the transition process.
2Area of stationary object
If the output gain is increased to expand service coverage, then the service coverage is improved, but oscillation occurs due to interference between link antenna and service antenna
Solution Approach 1:
The patent implements feedback by using the interference canceller to continuously monitor and estimate interference signals between the link antenna and service antenna. This feedback mechanism allows the system to detect oscillation conditions and adjust the gain accordingly, enabling higher output gain expansion for broader service coverage while maintaining signal stability through active interference management.
3Reliability
If the isolation between link antenna and service antenna is increased to prevent interference, then the interference cancellation is improved, but the device size increases making miniaturization difficult
Solution Approach 1:
The patent introduces an intermediary approach by implementing digital signal processing components (interference canceller and gain controller) that mediate the interference problem through software/algorithms rather than requiring increased physical isolation. This allows effective interference cancellation to be achieved through signal processing while maintaining a compact device size suitable for miniaturization.
Data Source
AI summary
An interference cancellation repeater includes: a first transmission/reception processing unit configured to convert a radio frequency (RF) input signal input via a link antenna communicatively coupled to a base station into a digital input signal; an interference canceller configured to cancel an interference signal from the digital input signal and to output an interference canceled signal; a second transmission/reception processing unit configured to convert the interference canceled signal into an RF output signal and to amplify the RF output signal; and a gain controller configured to detect a gain change of the interference cancellation repeater based on the interference canceled signal and to change a current gain of the interference cancellation repeater to a target gain by adjusting intensity of at least one of the RF input signal, the interference canceled signal, and the RF output signal when the gain change of the interference cancellation repeater is detected.