Adaptive Transmit Power Control Using Loop-Back Distortion Feedback
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Solution Overview
Problem
Current radio frequency transmitter systems face challenges in accurately determining the optimal power level for transmission, leading to inefficiencies and potential distortion, as they rely on pre-calibration methods that often require excessive safety margins and can result in sub-optimal performance due to uncertainties in component behavior and varying transmission paths.
Innovation Solution
The method involves adaptively determining transmit power by measuring output power during actual transmission, using a loop-back path and a Control and Measurement Module (CMM) to adjust gain settings in the power amplifier and pre-amplifier, ensuring minimal distortion and optimal power delivery through incremental power increases and distortion monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pre-calibration methods are used to determine transmit power, then the transmitter can be set up before deployment, but the system requires excessive safety margins leading to sub-optimal performance
Solution Approach 1:
The system performs preliminary calibration actions by establishing loop-back paths and configuring test modes before actual deployment. The calibration process sets up reference measurements and distortion thresholds in advance, allowing the transmitter to operate with optimized power levels rather than excessive safety margins.
Solution Approach 2:
The system implements feedback mechanisms where the receiver measures distortion levels of transmitted signals and reports back to the transmitter. This closed-loop feedback enables continuous optimization of transmit power levels, allowing the system to adapt to actual channel conditions and eliminate the need for excessive safety margins used in open-loop pre-calibration methods.
2Reliability
If higher transmit power is used to ensure reliable signal delivery, then signal reception is improved, but distortion increases causing demodulation errors
Solution Approach 1:
The system dynamically adjusts transmit power levels based on real-time distortion measurements and channel conditions. Rather than using fixed high power levels to ensure reliability, the transmitter continuously adapts its output power to maintain optimal signal quality, adjusting the balance between reliability and distortion based on actual operating conditions.
Solution Approach 2:
The system changes key operating parameters including transmit power level, modulation scheme, and coding rate based on measured distortion levels. When distortion increases, the system adjusts these parameters to maintain reliable communication, allowing flexible optimization of the reliability-distortion trade-off rather than being constrained to fixed high-power operation.
3Object-generated harmful factors
If lower transmit power is used to reduce distortion, then signal quality is improved, but data throughput decreases due to insufficient power at receivers
Solution Approach 1:
The system dynamically adjusts transmit power levels based on real-time distortion measurements and channel conditions. Rather than using fixed low power levels to minimize distortion, the transmitter continuously adapts its output power to maintain optimal signal quality, adjusting the balance between reliability and distortion based on actual operating conditions.
Solution Approach 2:
The system changes key operating parameters including transmit power level, modulation scheme, and coding rate based on measured distortion levels. When distortion increases, the system adjusts these parameters to maintain reliable communication, allowing flexible optimization of the reliability-distortion trade-off rather than being constrained to fixed high-power operation.
4Measurement precision
If closed loop feedback control systems are used to optimize power levels, then transmit power accuracy is improved, but system complexity increases and feedback provision is slow
Solution Approach 1:
The system implements feedback mechanisms where the receiver measures distortion levels of transmitted signals and reports back to the transmitter. This closed-loop feedback enables continuous optimization of transmit power levels, allowing the system to adapt to actual channel conditions and eliminate the need for excessive safety margins used in open-loop pre-calibration methods.
Solution Approach 2:
The system replaces complex mechanical calibration procedures with electronic measurement and control mechanisms. By using digital signal processing and automated feedback loops, the system achieves precise power level control without requiring complex manual calibration equipment or procedures, simplifying the overall control system while maintaining measurement precision.
Data Source
AI summary
Systems and methods for dynamically adjusting transmit gain in a transceiver. The gain is adjusted in order to provide the maximum gain. The amount of distortion is measured. The gain is increased until the distortion reaches a predetermined limit. The gain of several components can be adjusted independently.