Wireless Transmitter Power Control Circuit Gain Correction
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Solution Overview
Problem
Wireless communication systems face challenges in accurately controlling transmit power due to variations in transmitter components and aging, which affects the performance of both open loop and closed loop power control methods.
Innovation Solution
A circuit and method that utilize a gain corrector and estimator to adjust transmit power levels by aligning input and received signals through a delay, incorporating a gain estimation window and feedback mechanism to determine a measured gain signal and correct power target, thereby compensating for component variations and aging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If open loop power control is used, then the control method is simple, but it cannot compensate for variations in transmitter characteristics due to part-to-part variations and aging
Solution Approach 1:
The patent implements closed-loop power control by measuring the actual output power of the transmitter and comparing it with the target power level. The difference (error signal) is then fed back to adjust the power amplifier gain, enabling continuous compensation for component variations and aging effects, thus resolving the contradiction between simplicity and accuracy.
Solution Approach 2:
The system dynamically adjusts the power amplifier gain parameter based on measured output power deviations. By changing the gain parameter in response to actual operating conditions, the system maintains accurate power control despite part-to-part variations and aging, transforming a static simple control into a dynamic adaptive one.
2Measurement precision
If closed loop power control is used, then power measurement feedback improves accuracy, but the system complexity increases
Solution Approach 1:
The patent uses a feedback mechanism where the measured output power is compared with the target power, and the error signal adjusts the power amplifier gain. This feedback approach achieves accurate power control while keeping the system structure relatively simple, as it only requires basic measurement and adjustment components.
Solution Approach 2:
The system performs self-calibration by automatically measuring its own output power and adjusting its gain accordingly. This self-service capability eliminates the need for complex external calibration equipment or manual adjustment, reducing system complexity while maintaining high measurement precision.
3Reliability
If power control is adjusted frequently to compensate for aging, then accuracy is maintained, but the time required for estimation and adjustment increases
Solution Approach 1:
The patent performs gain estimation during dedicated estimation windows that are scheduled in advance. By preparing the estimation and adjustment process beforehand and scheduling it during appropriate time slots, the system minimizes the time impact on actual communication while maintaining continuous accuracy through periodic updates.
Solution Approach 2:
The system uses periodic estimation windows to update power control parameters at regular intervals. This periodic action allows the system to maintain accuracy by periodically compensating for aging effects, while the regular scheduling ensures that time loss is minimized and predictable, rather than requiring continuous real-time adjustment.
Data Source
AI summary
A circuit includes a transmit path to receive an input signal and generate an output signal to be output at a transmit power level according to a power target signal. The circuit also includes a gain corrector to output a signal for adjusting a power level of the output signal to correspond to the transmit power level. The signal for adjusting is based on the power target signal and a delay for time-aligning a first signal and a second signal.