AGC Power Estimation Using Threshold Crossing Rate
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Solution Overview
Problem
Existing automatic gain control (AGC) systems in mobile telecommunication systems require expensive hardware resources and high power consumption due to direct measurement of signal power, which is inefficient and costly.
Innovation Solution
An indirect estimation of signal power is achieved through measuring the threshold crossing rate of the received signal, using a variable gain amplifier with an exponential characteristic, and a power measurement block that calculates the power value from the threshold crossing rate, reducing hardware complexity and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement of signal power is used in AGC loop, then measurement precision is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent introduces an intermediary approach by using threshold crossing rate as a mediator to estimate signal power indirectly. Instead of directly measuring power through complex squaring and averaging operations, the system counts how often the signal crosses predefined thresholds, which correlates with power levels but requires simpler hardware implementation.
Solution Approach 2:
The patent replaces the traditional mechanical/computational approach of direct power measurement (squaring and averaging circuits) with a counting-based method. The threshold crossing rate measurement substitutes complex analog-to-digital conversion and mathematical operations with simpler digital counting logic, reducing hardware complexity while maintaining adequate measurement precision.
2Measurement precision
If direct measurement of signal power is used in AGC loop, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent introduces an intermediary approach by using threshold crossing rate as a mediator to estimate signal power indirectly. Instead of directly measuring power through complex squaring and averaging operations, the system counts how often the signal crosses predefined thresholds, which correlates with power levels but requires simpler hardware implementation.
Solution Approach 2:
The patent employs a simpler, less resource-intensive measurement method that consumes less power. The threshold crossing rate measurement uses basic digital counting logic instead of power-hungry analog circuits and complex digital signal processing, effectively using a 'cheaper' measurement approach in terms of energy consumption.
3Device complexity
If threshold crossing rate measurement is used for indirect power estimation, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent changes the measurement parameter from direct power (voltage squared) to threshold crossing rate (frequency of crossing events). By selecting appropriate threshold levels and counting crossing events over defined intervals, the system transforms a complex measurement into a simpler counting operation while maintaining sufficient precision for AGC control purposes.
Data Source
AI summary
A method for automatic gain control of an output signal generated from an input signal includes measuring power of the output signal. Measuring power of the output signal includes setting at least one power threshold, measuring a rate of crossing of the at least one power threshold by the output signal over an observation window, and deriving from the rate of crossing a measured power of the output signal. The method further includes providing a reference power, subtracting the measured power from the reference power to obtain an error signal, and mixing the input signal with the error signal. An analog-to-digital conversion is performed on a result of the mixing to obtain a gain-controlled output signal.