On-the-fly IQ Mismatch Compensation in RF Receivers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional solutions for IQ mismatch compensation in higher-order QAM communication systems are inadequate, as they either fail to compensate for temperature-induced mismatches or require power-consuming modifications that disrupt symbol signal reception.
Innovation Solution
A circuit and method within a receiver apparatus that performs on-the-fly IQ mismatch compensation by transforming data signals into frequency domain, calculating calibration parameters, and updating compensator coefficients to address IQ mismatches without interrupting data transmission or reception, using a transform circuit and calibration circuit coupled with a radio frequency receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional test tone signal method is used for IQ mismatch compensation, then fixed IQ mismatches can be compensated, but temperature-induced IQ mismatches cannot be compensated and the system cannot adapt to temperature changes
Solution Approach 1:
The patent implements dynamic IQ mismatch compensation by continuously updating calibration parameters based on temperature changes. The system transitions from static test-tone-based compensation to dynamic temperature-adaptive compensation using received signal statistics, allowing the compensator to adapt to temperature-induced variations in real-time
Solution Approach 2:
The system uses the received data signals themselves to perform calibration, eliminating the need for external test tone signals. The calibration process leverages the statistical properties of the received signals to automatically update compensation parameters, making the system self-calibrating without requiring separate test procedures
2Measurement precision
If sampling rate is doubled or IQ mixer phases are adjusted to compensate IQ mismatches, then compensation accuracy improves, but power consumption increases and data reception is interrupted during calibration
Solution Approach 1:
The patent enables continuous data reception during calibration by performing IQ mismatch compensation in the digital baseband domain. The calibration process operates on already-received data signals without requiring interruption of the RF reception chain, maintaining continuous useful action throughout the calibration process
Solution Approach 2:
The patent replaces hardware-based compensation methods (analog circuit modifications, local oscillator reconfiguration) with digital signal processing approaches. By performing calibration and compensation in the digital domain after ADC conversion, the system avoids power-consuming analog circuit modifications while achieving equivalent or superior compensation accuracy
3Measurement precision
If local oscillator is reconfigured or IQ mixer phase difference is adjusted for compensation, then IQ mismatch compensation is achieved, but data symbol reception is interrupted
Solution Approach 1:
The patent moves the calibration process from the RF/analog dimension to the digital baseband dimension. By performing IQ mismatch compensation after digital conversion using FFT-based methods on received data signals, the system eliminates the need to interrupt RF reception or reconfigure analog components, achieving compensation without time loss
Data Source
AI summary
A method employed by a circuit included within a receiver apparatus and configured for performing IQ mismatch compensation when receiver apparatus is operating under data reception mode includes: transforming a data signal, which is generated by a radio frequency receiver under the data reception mode, from time domain into a plurality of frequency bin signals in frequency domain; calculating to obtain at least one frequency domain calibration parameter according to the plurality of frequency bin signals in frequency domain; and, updating at least one coefficient parameter of IQ mismatch compensation according to the obtained at least one frequency domain calibration parameter, to make IQ mismatch compensation compensate IQ mismatch based on the updated at least one coefficient parameter.