Wireless Clock Synchronization via Phase Error Compensation
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Solution Overview
Problem
Magnetic Resonance Imaging (MRI) systems face challenges in accurately synchronizing the internal clock of a wireless RF coil with the system clock due to variable phase delays in wireless communication channels, leading to image artifacts and synchronization issues.
Innovation Solution
A wireless communication system with a base station and a mobile station that uses phase error detection and inverse channel models to compensate for variable phase delays, allowing for accurate clock synchronization by adjusting the phase of subsequent RF signals to reduce phase errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless communication is used between base station and mobile station, then ease of operation and flexibility are improved, but phase delay variations and synchronization accuracy deteriorate
Solution Approach 1:
The patent implements a feedback mechanism where the base station transmits reference signals to the mobile station, which estimates channel phase delays and feeds back this information. The base station then uses this feedback to calculate compensation values and adjust subsequent reference signals, creating a closed-loop system that continuously corrects phase errors caused by wireless channel variations.
Solution Approach 2:
The patent dynamically changes the phase parameter of transmitted reference signals based on estimated channel conditions. By adjusting the phase of subsequent reference signals using compensation values derived from channel estimates, the system adapts to varying wireless channel characteristics and maintains synchronization accuracy despite motion-induced delays.
2Adaptability or versatility
If motion between transmitter and receiver occurs, then adaptability to dynamic environments is improved, but time delay variations and clock synchronization deteriorate
Solution Approach 1:
The patent performs preliminary channel estimation using transmitted reference signals before actual data transmission. By estimating the channel phase delay in advance and calculating compensation values beforehand, the system prepares for subsequent transmissions, ensuring that time-critical operations maintain synchronization even when motion occurs between measurements.
Solution Approach 2:
The mobile station continuously monitors channel conditions and feeds back phase delay information to the base station. This feedback loop enables real-time detection of motion-induced delay variations and allows the base station to adjust reference signals accordingly, maintaining clock synchronization accuracy in dynamic environments.
3Device complexity
If conventional wireless synchronization methods are used, then device complexity is reduced, but image quality and phase error control deteriorate
Solution Approach 1:
The patent introduces reference signals as intermediary elements that mediate between the base station and mobile station for synchronization purposes. These reference signals serve as a common reference that both parties use to estimate and compensate for phase delays, providing a simple yet effective mechanism for maintaining synchronization without requiring complex hardware modifications.
Solution Approach 2:
The patent replaces complex mechanical or hardware-based synchronization mechanisms with signal-processing-based phase compensation. Instead of using precise mechanical timing devices or complex hardware synchronization circuits, the system uses software-based channel estimation and phase correction algorithms to achieve the required synchronization accuracy for image reconstruction.
Data Source
AI summary
A base station operating with a system clock includes a transmitter, a receiver, a phase error detector and a controller. The transmitter sends a first RF signal modulated onto a first RF carrier having a first phase over a first channel having a first variable phase delay to a mobile station. The mobile station recovers the first RF carrier, generates a second RF carrier, and synchronizes a local clock using the recovered first RF carrier and/or the second RF carrier. The receiver receives a second RF signal modulated onto the second RF carrier having a second phase over a second channel having a second variable phase delay. The phase error detector determines a phase error signal based on the first and second phases, and the controller generates a control signal based on the phase error signal. The control signal is applied to first and second inverse channel models.