Mixer IIP2 Calibration During Full-Duplex Receive Operation
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Solution Overview
Problem
Full-duplex receivers face performance degradation due to intermodulation distortion (IMD) products generated by strong transmit signals, which limit signal-to-noise ratio (SNR) and input power levels, and existing calibration methods require lengthy factory calibration times and offline processes.
Innovation Solution
A method and apparatus that utilize a correlation unit to measure IMD energy during full-duplex operation, employing machine learning and linear regression to quickly determine optimal IIP2DAC values for the mixer, reducing IMD distortion without the need for factory calibration or standby processes, using a 2D binary search technique to minimize computations and measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional factory calibration methods are used to optimize IIP2DAC values, then mixer linearity is improved, but calibration time increases significantly
Solution Approach 1:
The patent replaces traditional mechanical/physical calibration systems with a digital signal processing approach. A correlation unit measures IMD energy in the digital domain, and a processing system calculates optimal IIP2DAC values through computational algorithms, eliminating the need for lengthy physical factory calibration processes while maintaining mixer linearity optimization
Solution Approach 2:
The system performs self-calibration during normal full-duplex operation without requiring external factory calibration equipment or processes. The correlation unit continuously monitors IMD energy, and the processing system automatically adjusts IIP2DAC values based on real-time measurements, enabling the mixer to optimize its own linearity performance
2Manufacturing precision
If offline or standby calibration processes are used, then IIP2 optimization is achieved, but operational continuity is reduced
Solution Approach 1:
The patent enables continuous IIP2 optimization during normal full-duplex receive operations. The correlation unit measures IMD energy continuously, and the processing system updates IIP2DAC values in real-time without requiring the system to enter standby mode or interrupt operations, maintaining both optimization and operational continuity simultaneously
Solution Approach 2:
The system transitions from static offline calibration to dynamic real-time adjustment. The IIP2DAC values are continuously adapted based on current operating conditions and IMD measurements, allowing the mixer to maintain optimal linearity performance across varying signal conditions while operating continuously
3Measurement precision
If complex calibration algorithms are used to minimize IMD distortion, then measurement precision is improved, but computational complexity increases
Solution Approach 1:
The patent extracts only the essential measurement and calculation functions needed for IIP2 optimization. The correlation unit specifically measures IMD energy components, and the processing system calculates only the necessary IIP2DAC adjustment values, eliminating unnecessary computational complexity while maintaining measurement precision for the critical parameters
Data Source
AI summary
Aspects include an apparatus and a method for performing Second Order Input Intercept Point (IIP2) calibration of a Digital-to-Analog (DAC) during a full-duplex mode receive operation. In some aspects, a plurality of correlation values are obtained, indicating an amount of IMD energy of an RF signal, wherein the correlation values are associated with IIP2DAC values of a DAC. In some aspects, the apparatus can calculate a mixer bias value, based on the correlation values, and adjust a bias value of a mixer according to the determined bias value. The apparatus can obtain the correlation values, calculate the bias value, and adjust the bias value of the mixer during the full-duplex mode receive operation. In some aspects, the apparatus can thus improve IIP2 of the mixer and reduce IMD energy in a receive signal, during the receive operation, without the need of standby or factory calibration.