OTA Output Estimation Using DPD Linearity Gain Selection
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Solution Overview
Problem
Existing methods for estimating over-the-air (OTA) output of a device-under-test (DUT) are inaccurate due to uncertainties in compensating for gain and loss at measurement stages, which can lead to errors in the estimated output values.
Innovation Solution
A method and apparatus that utilize digital pre-distortion (DPD) models to compensate for nonlinearity of the transmitting device, allowing for the estimation of OTA output by determining the gain corresponding to a minimum value of the nonlinearity parameter, thereby eliminating the need to account for external factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If compensation for gain and loss at measurement stage is performed using known notated values, then the measurement process can be completed, but the estimation accuracy deteriorates due to process variation causing actual values to differ from notated values
Solution Approach 1:
The system uses the transmitting device itself to measure its own output power through DPD modeling and nonlinearity parameter analysis, eliminating the need for external measurement equipment with uncertain calibration values. The device self-determines its rated output by identifying the gain corresponding to minimum nonlinearity parameter, making the measurement independent of external measurement stage characteristics.
Solution Approach 2:
The patent replaces the physical measurement system (antennas, transmission lines, power meters) with a signal processing-based method using DPD models. Instead of measuring power directly with external equipment that has calibration uncertainties, the system uses digital signal processing to analyze nonlinearity parameters and derive output power from the relationship between gain and nonlinearity.
2Measurement precision
If external measurement equipment is used to measure OTA output, then the measurement can be performed, but external factors such as measurement stage gain and loss introduce errors
Solution Approach 1:
The patent extracts the measurement function from the external measurement equipment and relocates it to the transmitting device itself. By performing the measurement internally through DPD-based nonlinearity analysis, the system removes the measurement device and its associated external factors (antennas, transmission lines, power meters) from the measurement process, thereby eliminating their influence on measurement accuracy.
Solution Approach 2:
The patent introduces DPD modeling and nonlinearity parameter analysis as an intermediary method between the transmitting device and the goal of determining output power. Instead of directly measuring power with external equipment, the system uses the nonlinearity parameter as an intermediate indicator that correlates with output power, allowing indirect but more accurate determination without external measurement stage influence.
Data Source
AI summary
A method for estimating an over the air (OTA) output performed by a transmitting device is provided. The method includes selecting a digital pre-distortion (DPD) model to compensate for nonlinearity of the transmitting device at a rated output, obtaining characteristic information related to a relationship between a gain of the transmitting device and a nonlinearity parameter, based on the selected DPD model, and determining a gain corresponding to a minimum value of the nonlinearity parameter as a gain for the rated output, based on the characteristic information.