DPD Coefficient Interpolation for Microwave Calibration Accuracy
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Solution Overview
Problem
Existing methods for determining digital pre-distortion (DPD) calibration coefficients in microwave communications devices result in significant errors, leading to inadequate calibration and performance issues due to the polynomial approximation method used for adapting to varying working states of the analog module.
Innovation Solution
A DPD calibration coefficient control method that utilizes interpolation based on pre-obtained coefficients for multiple typical working states, including extreme and intermediate states, to accurately determine and adjust calibration coefficients for specific working states, ensuring precise calibration by considering parameters like output power, frequency, and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If polynomial approximation method is used to calculate DPD calibration coefficient for varying working states, then implementation complexity is reduced, but calibration accuracy deteriorates significantly
Solution Approach 1:
The patent segments the working state space into multiple typical states (extreme states and intermediate states). For each segmented state, a separate DPD calibration coefficient is pre-calculated and stored. When calibration is needed, the system selects the coefficient corresponding to the current working state from the segmented set, avoiding the need for complex real-time polynomial calculations while maintaining high accuracy.
Solution Approach 2:
The patent performs preliminary calculation of DPD calibration coefficients for all typical working states (extreme and intermediate states) in advance. These pre-calculated coefficients are stored in a lookup table. During actual operation, the system only needs to query the table based on the current working state, eliminating the need for complex real-time polynomial approximation calculations.
2Ease of operation
If DPD calibration coefficient is obtained for extreme working state only, then measurement and calibration process is simplified, but calibration effectiveness deteriorates for other working states
Solution Approach 1:
The patent divides the working state range into multiple典型 states including extreme states (maximum and minimum output power) and intermediate states. Each segmented state has its own pre-calculated DPD calibration coefficient, ensuring that calibration is effective across the entire working range rather than only at extreme points.
Solution Approach 2:
The patent performs preliminary calibration measurements for multiple typical working states (extreme and intermediate states) and pre-calculates the corresponding DPD calibration coefficients. These coefficients are stored for quick retrieval during operation, ensuring calibration effectiveness is maintained across all working states without requiring complex real-time adjustments.
Data Source
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AI summary
A DPD calibration coefficient control method and apparatus are applied to a microwave communications device that includes an analog module and a digital module, and can ensure a DPD calibration effect. The method includes: determining, by means of interpolation and according to DPD calibration coefficients that are corresponding to at least 2N typical working states of the analog module and that are obtained in advance, a specified DPD calibration coefficient corresponding to a specified working state of the analog module, where N is a quantity of parameters representing a working state of the analog module; and controlling a DPD calibration coefficient according to the determined specified DPD calibration coefficient corresponding to the specified working state of the analog module.