DPD Coefficient Estimation for PA Linearity and Signal Quality
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Solution Overview
Problem
Existing DPD solutions are inflexible, restricting the adjustment of pre-distortion coefficients, leading to inefficiencies in power amplifier operation, which results in increased adjacent channel leakage ratio (ACLR) and error vector magnitude (EVM), affecting signal quality and decoding probability.
Innovation Solution
The development of a DPD estimator circuitry that determines adjustable pre-distortion coefficients using a dynamic deviation reduction (DDR) or generalized memory polynomial (GMP) equation, allowing for customizable terms and efficient resource utilization, minimizing processor usage and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If existing DPD solutions use fixed pre-distortion coefficients, then device complexity is reduced, but signal quality deteriorates due to increased ACLR and EVM
Solution Approach 1:
The patent implements dynamic pre-distortion coefficients that can be adjusted based on power amplifier operating conditions. The DPD estimator circuitry continuously updates coefficients to track PA nonlinearities across different power levels, transforming the static coefficient system into a dynamic one that adapts to changing conditions, thereby improving signal quality without excessive complexity increase
Solution Approach 2:
The system changes the parameters of pre-distortion coefficients based on operating conditions. By monitoring power levels and adjusting the DPD coefficients accordingly, the system optimizes linearization performance across different operating points, reducing ACLR and EVM while maintaining manageable device complexity through parameter adaptation
2Object-affected harmful factors
If DPD coefficients are made adjustable to improve signal quality, then ACLR and EVM are reduced, but device complexity and processing requirements increase
Solution Approach 1:
The patent segments the DPD coefficient adjustment into discrete power levels or operating regions. Rather than continuous complex adjustment, the system divides the operating range into segments and applies appropriate coefficients for each segment, reducing the overall complexity while effectively addressing ACLR and EVM across the full power range
Solution Approach 2:
The DPD estimator circuitry is designed to automatically update coefficients based on feedback from the power amplifier output. The system self-adjusts without requiring external intervention or complex control mechanisms, reducing the burden on external processing while improving signal quality through autonomous coefficient optimization
Data Source
AI summary
An example apparatus includes: programmable circuitry to receive an input signal, a digital pre-distorter (DPD) output signal, and a power amplifier (PA) feedback signal; populate a partial matrix with a threshold number of rows of equation terms; compute a respective observation terms for each row in the threshold number of rows; reduce the partial matrix into a Hermitian matrix and reduce the observation terms into a vector; accumulate the Hermitian matrix and the vector onto the memory; regularize, after a determination that a threshold number of Hermitian matrices have been accumulated, the memory to form an output matrix; and pre-distort the input signal using the output matrix.