V2X UE Synchronization Source Switching for Tunnel Signal Loss
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Solution Overview
Problem
User equipment (UE) in V2X communication systems may lose synchronization with the synchronization source, such as GNSS, when entering tunnels or garages, leading to failure in determining valid transmission resources and normal data transmission.
Innovation Solution
The UE determines a first synchronization source based on configuration information from the base station, and when synchronization fails, it determines a second synchronization source and corresponding transmission resource, allowing data transmission to continue on a different carrier frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE uses a single synchronization source (e.g., GNSS) for V2X data transmission, then the transmission timing accuracy is improved, but the reliability deteriorates when the UE enters tunnels or garages where the synchronization source signal is unavailable
Solution Approach 1:
The patent combines multiple synchronization sources (GNSS and eNB timing) into a unified synchronization mechanism. The UE can switch between these sources depending on availability, merging their functionalities to ensure continuous synchronization. This resolves the contradiction by maintaining timing accuracy through GNSS when available while ensuring reliability through eNB fallback when GNSS is unavailable.
Solution Approach 2:
The patent changes the synchronization source parameter dynamically based on signal availability. When GNSS signal is lost (entering tunnel/garage), the system transitions from GNSS-based synchronization to eNB-based synchronization. This parameter change allows the system to maintain reliable operation across different environmental conditions while preserving timing accuracy when the primary source is available.
2Adaptability or versatility
If the transmission carrier and service carrier are located on different frequencies, then the adaptability of the V2X system is improved, but the device complexity increases due to multi-carrier synchronization management
Solution Approach 1:
The patent implements a universal synchronization mechanism that works across multiple carrier frequencies. The same synchronization source (either GNSS or eNB) is used to provide timing reference for both service carrier and transmission carrier, even when they operate on different frequencies. This multi-functional approach allows the system to handle different frequency configurations without proportionally increasing complexity, as the synchronization management logic remains unified rather than requiring separate mechanisms for each carrier.
Data Source
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AI summary
Embodiments of the present invention provide a data transmission method and apparatus. The method includes: receiving, by user equipment UE, first synchronization source configuration information on a first carrier; determining, a first synchronization source based on the first synchronization source configuration information; determining that synchronization with the first synchronization source fails; determining a second synchronization source and a transmission resource; and transmitting data on a second carrier by using the determined transmission resource and based on the second synchronization source, where the first synchronization source is used to provide the UE with a synchronization clock required for transmitting the data on the second carrier, and a frequency of the first carrier is different from a frequency of the second carrier. In the embodiments of the present invention, normal data transmission can still be implemented after the synchronization between the user equipment and the first synchronization source fails.