Receiver-Side PA Linearization for Compression-Region Efficiency
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Solution Overview
Problem
Existing linearization techniques suffer from efficiency degradation due to signal predistortion at the transmitter side, leading to increased peak-to-average power ratio (PAPR) and decreased power efficiency in power amplifiers, especially when operating near compression regions.
Innovation Solution
A method and system that compensates for transmitter nonlinearity at the receiver side using a cumulative distribution function (CDF) based algorithm to estimate amplitude-to-amplitude (AM/AM) nonlinearity, combined with transmitter-phase predistortion for improved efficiency and Bit Error Rate (BER) performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If digital predistortion is applied at the transmitter side to compensate for PA nonlinearity, then signal linearity is improved, but peak-to-average power ratio increases and power efficiency deteriorates
Solution Approach 1:
The patent inverts the location of the linearization function from the transmitter side to the receiver side. Instead of applying predistortion before the PA at the transmitter, the invention applies post-distortion compensation after the PA at the receiver. This inversion allows the PA to operate in its high-efficiency nonlinear region while still achieving signal linearity through the receiver-side compensation algorithm that uses CDF-based amplitude distribution comparison.
2Use of energy by moving object
If power amplifier operates in compression region to maintain high power efficiency, then power efficiency is improved, but signal distortion increases
Solution Approach 1:
The patent implements a feedback mechanism where the receiver measures the output signal's amplitude distribution, compares it with the expected input signal distribution using CDF analysis, and uses this information to estimate and compensate for the PA's nonlinear distortion. This feedback loop enables the system to operate the PA in the compression region for high efficiency while maintaining signal linearity through intelligent post-processing.
3Manufacturing precision
If transmitter-side predistortion is used to compensate for nonlinearity, then distortion is reduced, but device complexity increases due to additional up and down-conversion circuits
Solution Approach 1:
The patent extracts the linearization function from the transmitter hardware and relocates it to the receiver's baseband processing unit. By taking out the complex predistortion circuits (mixers, filters, quadrature modulators) from the transmitter path and implementing the compensation algorithm in the receiver's digital signal processor, the invention reduces transmitter device complexity while maintaining signal linearity through software-based post-compensation.
Data Source
AI summary
A method for distortion compensation in a transmission link comprising obtaining information of an amplitude distribution of a signal prior to being transmitted by a transmitter, receiving the transmitted signal at a receiver and determining a received signal amplitude distribution, comparing the received signal amplitude distribution to the amplitude distribution of the signal prior to transmission and using results of the comparison to estimate the AM/AM non-linearity in the transmitter.