Channel Response Ratio Computation for Zero-IF IQ Mismatch Correction
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Solution Overview
Problem
Zero-IF transmitters face challenges in maintaining accurate amplitude and phase relationships between in-phase (I) and quadrature (Q) signals due to IQ gain/phase imbalance and DC offset, leading to LO leakage, which complicates signal transmission and may violate regulatory emission standards.
Innovation Solution
A channel response generating module computes a ratio of channel responses between image and traffic signal frequency bins, allowing for the adjustment of baseband signals to compensate for IQ mismatch and LO leakage, enabling quick convergence to correct signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequent transmission of signals is performed to estimate channel responses, then channel response estimation accuracy is improved, but regulatory emission standards are violated
Solution Approach 1:
The patent applies partial action by estimating channel responses only at specific time instants when traffic signal channel responses change, rather than continuously or frequently. This selective estimation approach maintains adequate channel response accuracy while significantly reducing the number of estimation operations, thereby preventing violations of regulatory emission standards.
Solution Approach 2:
The patent changes the parameter of estimation frequency from continuous/frequent to event-driven (based on channel response changes). By monitoring whether channel responses have changed and only estimating when necessary, the system maintains measurement precision while controlling transmission activity to comply with emission standards.
2Measurement precision
If IQ mismatch correction is applied, then signal transmission accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements feedback by looping back the IQ RF signals through a feedback chain and correlating the IQ baseband signal with the observed feedback signal. This feedback mechanism enables automatic estimation of channel responses and IQ mismatch parameters, improving signal transmission accuracy while managing complexity through automated correction processes.
Solution Approach 2:
The system performs self-correction by automatically estimating channel responses and IQ mismatch parameters using the feedback chain, without requiring external intervention. The correction is applied autonomously to compensate for impairments, improving transmission accuracy while the self-service nature helps manage system complexity.
Data Source
AI summary
A channel response generating module and method for generating a channel response based on a ratio of a channel response corresponding to an image signal frequency bin in relation to a channel response corresponding to a traffic signal frequency bin, or a channel response corresponding to a first frequency bin in relation to a channel response corresponding to a second frequency bin, and a zero-IF signal transmitter employing the channel response generating module and method to efficiently suppress image signals or compensate traffic signals during transmission of IQ RF signals.