TDD Repeater Gain Control for Oscillation and Interference Protection
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Solution Overview
Problem
Existing network protection standards for wireless communication repeaters do not adequately address the challenges posed by time division duplex (TDD) frequency bands, which include varying downlink power, extreme fading environments, MIMO effects, and downlink uplink decoupling, leading to potential interference and amplifier saturation.
Innovation Solution
A TDD repeater system that includes a signal detector to measure received signal power, adjust uplink system noise power or gain based on downlink signal measurements, and implement oscillation detection mechanisms to prevent amplifier saturation by reducing gain when oscillation is detected, using a controller to manage amplification paths and ensure compliance with regulatory standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amplifier gain is increased to improve signal quality, then signal amplification is improved, but amplifier saturation and oscillation occur
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors the amplified signal for oscillation conditions and adjusts the amplifier gain accordingly. When oscillation is detected, the controller reduces the gain to prevent saturation, and when oscillation is not present, the gain is increased to improve signal quality. This dynamic feedback control resolves the contradiction by automatically adapting the amplification level to current signal conditions.
Solution Approach 2:
The patent makes the amplifier gain dynamic rather than fixed. The controller adjusts the gain in real-time based on detected signal conditions, transitioning between different amplification states to optimize performance while avoiding saturation. This dynamic adjustment allows the system to adapt to varying signal conditions and prevent harmful effects.
2Reliability
If repeater amplifies both uplink and downlink signals simultaneously, then communication coverage is improved, but interference between directions occurs
Solution Approach 1:
The patent implements periodic switching between uplink and downlink amplification modes synchronized with the TDD frame structure. The controller alternates between amplifying uplink signals during uplink subframes and downlink signals during downlink subframes, with guard periods preventing simultaneous amplification in both directions. This periodic action eliminates interference while maintaining comprehensive communication coverage.
Solution Approach 2:
The patent segments the amplification function into separate uplink and downlink paths that are activated at different times. By dividing the communication into distinct uplink and downlink phases with guard periods, the system prevents interference between directions while providing full-duplex communication coverage through time-division multiplexing.
3Reliability
If guard period is extended to prevent interference, then oscillation prevention is improved, but signal transmission time is increased
Solution Approach 1:
The patent applies partial guard periods only where necessary to prevent oscillation, rather than extending guard periods uniformly across all subframes. The controller dynamically adjusts guard period length based on detected oscillation conditions, applying minimal necessary protection to maintain signal quality while minimizing transmission time loss.
Data Source
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AI summary
A technology is described for a time division duplex (TDD) repeater with network protection. The TDD repeater can comprise a first port, a second port, and one or more amplification paths coupled between the first port and the second port. The TDD repeater can comprise a signal detector configured to measure a received signal power for a downlink (DL) signal in a first set of one or more TDD DL subframes. The TDD repeater can be further configured to adjust an uplink (UL) noise power or gain of the one or more amplification paths based on the received signal power for the DL signal in the first set of the one or more TDD DL subframes.