Power Amplifier Predistortion Factor Calibration Without Complex Division
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Solution Overview
Problem
Current methods for computing complex division in RF power amplifiers require resource-intensive data conversion and division operations, which are inefficient and consume significant resources.
Innovation Solution
The method involves iteratively assigning complex values to a predistortion factor until the product of the baseband signal sample and the complex factor converges with the output signal sample, eliminating the need for preliminary data conversion and division operations by storing the complex factor in memory associated with the baseband signal sample.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional complex division techniques (coordinate transformation or complex conjugate multiplication) are used to compute complex gain, then the complex gain can be accurately calculated, but resource consumption increases due to required data conversion operations and division operations
Solution Approach 1:
The patent extracts and eliminates the resource-intensive data conversion operations (coordinate transformation or complex conjugate multiplication) from the complex division process. By using an iterative approach that directly converges to the complex gain value without these preliminary conversions, the invention removes the harmful resource consumption while preserving calculation accuracy.
Solution Approach 2:
The patent employs a dynamic iterative approach where the complex gain is refined through successive approximations. Instead of using static conversion formulas, the algorithm dynamically adjusts the complex gain estimate in each iteration, converging to the accurate value while avoiding fixed resource-intensive conversion steps.
2Ease of manufacture
If data conversion operations (coordinate transformation or complex conjugate multiplication) are performed before division, then complex division can be executed, but the computational complexity and resource requirements increase
Solution Approach 1:
The patent performs preliminary initialization of the complex gain estimate and iteration counter before the main computational loop. This preliminary setup establishes the iterative framework that eliminates the need for complex data conversion operations during the main computation, reducing overall computational complexity.
Solution Approach 2:
The patent replaces the mechanical/mathematical system of coordinate transformation and complex conjugate multiplication with a simpler iterative numerical approach. This substitution eliminates the need for complex algebraic manipulations and data conversions, reducing computational complexity while maintaining accuracy.
Data Source
AI summary
A baseband signal is generated as a sequence of complex sample values at a predetermined sample rate. A sample of the baseband signal is captured as is a sample of an output signal generated by a power amplifier from the captured sample of the baseband signal. Complex values are iteratively assigned to a complex factor intended for predistorting data such that the product of the baseband signal sample and the complex factor converges towards equivalence with the output signal sample with each iterative assignment of the complex values to the complex factor. The complex factor is stored in memory at an address associated with the value of the captured baseband signal sample.