Repeater Amplifier Gain Control for Noise Reduction
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Solution Overview
Problem
In wireless communication systems, repeaters can increase noise levels at base stations, reducing the signal-to-noise ratio and causing loss of coverage area due to the amplification of signals and subsequent radiation back to base stations.
Innovation Solution
A method and apparatus for controlling repeater amplifier gain factors based on received signal strength, automatically adjusting the gain values of forward and reverse channel amplifiers to minimize noise interference, with thresholds set to optimize signal amplification and reduce noise levels, allowing the repeaters to operate independently without supervision from wireless service providers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the repeater amplifies and radiates signals back to base stations, then the coverage area is extended, but the noise level at base stations increases reducing the signal-to-noise ratio
Solution Approach 1:
The repeater dynamically adjusts its amplifier gain based on the received signal strength from the base station. When the received signal strength exceeds a threshold, the repeater reduces its amplification gain to minimize noise injection into the base station receiver. When the received signal strength is below the threshold, the repeater increases its gain to maintain coverage. This dynamic adjustment resolves the contradiction between extending coverage and minimizing noise interference.
Solution Approach 2:
The repeater continuously monitors the received signal strength from the base station and uses this feedback to control its amplifier gain. The feedback mechanism allows the repeater to automatically adjust its operation to maintain optimal performance, preventing excessive noise injection when the base station receiver is desensitized while ensuring adequate amplification when needed for coverage extension.
2Device complexity
If the repeater uses fixed gain amplification, then the implementation is simple, but the noise interference at base stations cannot be minimized
Solution Approach 1:
The system transitions from fixed gain to dynamic gain control by monitoring received signal strength and adjusting amplifier gain accordingly. This dynamic approach increases complexity slightly but effectively minimizes noise interference by reducing amplification when the base station receiver is in a sensitive state, while maintaining simplicity through automatic control based on signal strength thresholds.
3Area of stationary object
If the repeater amplifies signals from multiple base stations and sectors, then the signal coverage is improved, but the capacity of base stations decreases due to increased noise
Solution Approach 1:
The repeater dynamically adjusts its amplification gain based on real-time signal strength measurements from base stations. When a base station's receiver becomes desensitized due to amplified noise, the repeater reduces its gain to protect the base station's capacity. This dynamic control allows the system to maintain signal coverage while preventing degradation of base station capacity through selective amplification adjustment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces noise interference at base stations, maintaining or improving coverage area by dynamically adjusting amplifier gains in response to signal strength, thereby enhancing the capacity and reliability of wireless communication systems.
Implementation Method 1
The repeater amplifies the power of these intercepted signals and sends amplified versions of these signals to the mobile station or the base station
Implementation Method 2
The noise is typically thermal noise generated from active devices in the repeater
Data Source
AI summary
Controlling a cellular radio frequency repeater amplifier and their gain factors. In preferred embodiments, the method is used in personal home repeaters that may be used by wireless services users. The repeaters are preferably configured to automatically control their setting without requiring supervision or control by the wireless service provider. The wireless provider also need not have knowledge of where the repeater devices are placed within the network. The preferred system and methods reduce potential problems that may arise when repeaters with fixed gain are placed within close proximity of a cell site. The preferred methods shut down the forward and reverse amplifiers based on the received signal level from the base station.