I/Q Calibration via Loopback Path for Transceiver Mismatch
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems face performance degradation due to in-phase (I)/quadrature (Q) mismatches in transceivers, which occur when local oscillator components are not properly calibrated, leading to increased packet error rates and error vector magnitude deterioration, especially in high-modulation schemes like 16QAM, 64QAM, or 256QAM, and require calibration methods that do not disrupt ongoing communication.
Innovation Solution
A real-time I/Q calibration method that configures a loopback path between the transmitter and receiver, transmits a preconfigured signal, identifies an image signal, determines gain and phase error values, and performs calibration based on these values without stopping communication, using a subcarrier arrangement where the original and image signals do not overlap, allowing for continuous operation and adaptation to environmental changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional I/Q calibration methods are used, then I/Q mismatch can be corrected, but communication must be interrupted to perform calibration
Solution Approach 1:
The patent applies preliminary action by inserting a calibration signal at the beginning of each TTI (Transmission Time Interval) before actual data transmission. This allows the transceiver to perform I/Q calibration in advance using the calibration signal, ensuring calibration accuracy is achieved before communication begins, thus resolving the contradiction between calibration accuracy and communication continuity.
Solution Approach 2:
The patent implements continuity of useful action by designing the calibration signal to be transmitted within the existing TTI structure without requiring separate calibration time slots. The calibration process occurs concurrently with the communication framework, allowing calibration to continue seamlessly across multiple TTIs while maintaining ongoing communication, thus eliminating service interruption.
2Ease of manufacture
If factory calibration is performed, then initial I/Q balance can be established, but calibration cannot adapt to environmental changes during operation
Solution Approach 1:
The patent applies periodic action by implementing runtime calibration that occurs at regular intervals during operation. The transceiver continuously receives calibration signals and performs I/Q calibration dynamically, allowing the system to adapt to environmental changes such as temperature variations and component aging. This periodic recalibration ensures the transceiver maintains optimal performance throughout its operational lifecycle, resolving the contradiction between ease of initial calibration and adaptability to environmental changes.
Data Source
AI summary
An apparatus and method are provided for a communication scheme for converging a 5G communication system for supporting a higher data transfer rate than a post-4G system with the IoT technology. A method includes configuring a loopback path between a transmitter and a receiver; transmitting a preconfigured signal from the transmitter to the receiver through the loopback path; identifying an image signal, wherein the image signal includes a distorted signal of the preconfigured signal; determining a gain error value and a phase error value based on the preconfigured signal and the image signal; and performing I/Q calibration based on the gain error value and the phase error value. A subcarrier in which the preconfigured signal is transmitted and a subcarrier in which the image signal is generated do not overlap.