Multi-Cell MIMO Processing for Nonlinear Crosstalk Compensation
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Solution Overview
Problem
Conventional signal processing algorithms for MIMO systems fail to effectively compensate for complex distortions, interactions, and crosstalk, leading to significant degradation in signal quality due to linear and nonlinear components and unwanted correlations between multiple input signals.
Innovation Solution
A method and pre-compensator for MIMO systems that involve generating a pre-distorted signal using a matrix of processing cells to estimate and adjust for impairments, compensating for both linear and nonlinear distortions and crosstalk across multiple inputs and outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional signal processing algorithms are used for MIMO systems, then the system structure remains simple, but signal quality degrades significantly due to uncompensated distortions and crosstalk
Solution Approach 1:
The MIMO processing architecture is segmented into multiple independent processing cells, where each cell handles a specific input-output signal pair. This segmentation allows parallel processing of multiple signals while maintaining manageable complexity within each cell, effectively compensating for distortions and crosstalk without requiring an overwhelmingly complex monolithic structure.
Solution Approach 2:
The system performs preliminary distortion compensation and crosstalk cancellation by processing signals before they are fully corrupted by nonlinearities and interactions. Pre-distortion techniques are applied to counteract anticipated distortions, and early cancellation of interference signals prevents degradation before it occurs, thereby maintaining signal quality without requiring post-processing complexity.
2Reliability
If a matrix of processing cells is implemented to compensate for all distortions and interactions, then signal quality improves significantly, but the processing architecture becomes more complex
Solution Approach 1:
Each processing cell in the matrix is designed with universal functionality to handle multiple types of signal processing tasks including linear distortion compensation, nonlinear distortion compensation, and crosstalk cancellation. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby improving signal quality through comprehensive compensation while controlling overall architectural complexity.
3Device complexity
If multiple signals are transmitted through a single branch RF front-end at different carrier frequencies, then hardware complexity is reduced, but complex distortions and interactions between signals increase
Solution Approach 1:
The baseband processing stage serves as an intermediary between the multiple carrier frequency signals and the single branch RF front-end. At baseband, signals are processed separately through the matrix of processing cells to compensate for distortions and crosstalk before being up-converted to different carrier frequencies. This intermediary processing prevents harmful interactions from manifesting in the RF domain while maintaining hardware simplicity.
Data Source
AI summary
A method for predistortion including receiving a plurality of input signals forming a multiple-input signal in a multiple-input multiple-output system. generating a pre-distorted multiple-input signal from the received multiple-input signal, generating a multiple-output signal by feeding the pre-distorted multiple-input signal into a multiple-input and multiple-output transmitter, estimating impairments generated by the multiple-input and multiple-output transmitter, the impairments including nonlinear crosstalk between distinct ones of the plurality of input signals; and adjusting the pre-distorted multiple-input signal to compensate for the estimated impairments.