IQ Mismatch Compensation Using Iterative IRR Optimization
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Solution Overview
Problem
Communication systems face performance degradation due to in-phase (I) and quadrature (Q) mismatch (IQMM) in transmitters and receivers, leading to interference and reduced signal quality, which existing technologies have not adequately addressed.
Innovation Solution
An iterative method is employed to optimize IQ mismatch compensator (IQMC) parameter values by generating candidate parameter sets and determining the optimal values that maximize performance metrics such as image rejection ratio (IRR), signal-to-interference-plus-noise ratio (SINR), and signal-to-image ratio (SImR) using gradient ascent or descent techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If iterative optimization methods are used to maximize IRR, then image rejection performance is improved, but computational complexity and processing time increase
Solution Approach 1:
The patent transforms the complex multi-parameter IQ mismatch compensation problem into a simplified one-dimensional optimization by changing parameters from complex I/Q path parameters to real-valued pre-compensator parameters (α, β, γ, δ) that can be optimized using gradient ascent on a single performance metric (IRR), reducing computational complexity while maintaining optimization effectiveness
Solution Approach 2:
The patent implements feedback by using the calculated IRR value as a performance metric that guides the gradient ascent optimization process, where the IRR calculation feedback from each parameter set informs the next parameter adjustment, creating a closed-loop optimization system that converges to optimal values
2Reliability
If multiple performance metrics are optimized simultaneously, then overall system performance is improved, but optimization complexity increases
Solution Approach 1:
The patent extracts and prioritizes the most critical performance metric (IRR) from multiple possible metrics (IRR, SINR, SImR), focusing optimization efforts on maximizing IRR as the primary objective function. This extraction approach simplifies the optimization problem by dealing with one dominant metric rather than simultaneously optimizing multiple competing metrics
Solution Approach 2:
The patent segments the optimization process into distinct phases: first optimizing pre-compensator parameters to maximize IRR, then using those optimized values as fixed parameters for subsequent signal processing. This segmentation allows each phase to be optimized independently, reducing overall optimization complexity
Data Source
AI summary
A method of optimizing at least one IQMC parameter value for an IQMC includes: generating a set of tested IQMC candidate parameter values by performing an iterative method including selecting a first IQMC candidate parameter value for the at least one parameter of the IQMC; determining, using the first IQMC candidate parameter value, a performance metric value that comprises at least one of (i) an image rejection ratio (IRR) value, (ii) a signal-to-interference-plus-noise ratio (SINR) value, or (iii) a signal-to-image ratio (SImR) value; and determining a second IQMC candidate parameter value that is an update to the first IQMC candidate parameter value. The method of optimizing at least one IQMC parameter value for an IQMC further includes determining an IQMC candidate parameter value of the set of tested IQMC candidate parameter values that optimizes the performance metric.


