RF Repeater Gain Margin Control via Signal Decorrelation
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Solution Overview
Problem
Non-translating repeaters face performance issues due to insufficient isolation between transmit and receive antennas, leading to oscillation and instability, as existing methods for measuring gain margin are not adaptive and can cause service interruptions during measurement.
Innovation Solution
A repeater system that uses frequency shifting to decorrelate input and feedback signals, allowing for continuous measurement and adjustment of gain margin without interrupting service, by adding a small frequency shift to the repeated signals and cross-correlating them with the receive signals to separate input and feedback levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gain margin measurement is performed in traditional repeater systems, then stability can be assessed, but service interruptions occur during measurement
Solution Approach 1:
The patent implements continuous gain margin measurement by injecting test signals throughout normal operation rather than pausing service. The measurement process occurs continuously in the background, allowing the repeater to maintain stable operation while constantly monitoring gain margin without interrupting the useful communication function.
Solution Approach 2:
The patent introduces test signal injection as an intermediary mechanism that allows gain margin measurement to occur without directly interrupting service. By using a separate test signal path and correlating received signals with known test signals, the system can assess stability while normal communication continues uninterrupted.
2Device complexity
If antenna isolation is insufficient in non-translating repeaters, then device complexity is reduced, but oscillation and instability occur
Solution Approach 1:
The patent implements feedback control by continuously measuring gain margin through test signal injection and correlation. The measured gain margin information is used to adjust the repeater gain dynamically, ensuring that the system maintains stable operation even with insufficient physical antenna isolation. This closed-loop feedback mechanism compensates for the lack of isolation without adding complex structural elements.
Solution Approach 2:
The patent dynamically adjusts the repeater gain parameter based on measured gain margin conditions. By changing the gain parameter in response to measured conditions, the system maintains stability without requiring increased antenna isolation. The gain is adjusted to ensure it remains below the isolation level, preventing oscillation while maintaining signal repetition functionality.
3Area of stationary object
If repeater gain is increased to improve signal coverage, then coverage area is extended, but oscillation risk increases due to insufficient antenna isolation
Solution Approach 1:
The patent uses continuous gain margin measurement as feedback to dynamically control the repeater gain. The system monitors the difference between repeater gain and antenna isolation, and adjusts the gain accordingly. This allows the repeater to operate at maximum stable gain, extending coverage area while preventing oscillation through real-time feedback control.
Solution Approach 2:
The patent implements dynamic gain adjustment rather than fixed gain settings. The repeater gain is continuously adapted based on measured gain margin conditions, allowing the system to optimize coverage area while maintaining stability. This dynamic approach enables the repeater to respond to changing conditions and maintain optimal operation without oscillation.
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
Enables adaptive gain adjustment to maintain stability and prevent oscillation, ensuring continuous service by allowing for real-time measurement and adjustment of gain margin without service disruptions.
Implementation Method 1
a frequency shifting circuit to add a frequency shift and provide repeated signals that are slightly frequency-shifted from the input signals originally received by the repeater
Implementation Method 2
Processing circuitry uses the frequency-shifted repeated signals to determine gain margin
Data Source
AI summary
An apparatus for repeating signals includes a receive antenna for capturing a receive signal, processing circuitry for processing the receive signal to form a repeated signal, and a transmit antenna for transmitting the repeated signal. The processing circuitry includes gain circuitry for gain in the repeated signal and decorrelation circuitry configured for modifying the repeated signal with respect to the receive signal to thereby decorrelate the repeated signal from the receive signal. The processing circuitry further comprises circuitry configured for calculating a gain margin for the apparatus utilizing the decorrelated receive and repeated signals.