V2V Timing Synchronization via Fingerprint Database
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Solution Overview
Problem
Current vehicle-to-vehicle (V2V) and vehicle-to-everything (V2X) communication systems face challenges in maintaining timing synchronization, especially when Global Navigation Satellite System (GNSS) signals are unreliable, leading to potential service outages and interference issues.
Innovation Solution
The implementation of a computationally simple method for establishing and maintaining timing synchronization through the use of timing fingerprints, which store SFN-DFN offsets and synchronization source information, allowing devices to switch between synchronization sources and correct for timing inconsistencies, thereby minimizing service outages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS-based timing synchronization is used in V2V communications, then timing synchronization accuracy is improved, but service reliability deteriorates when GNSS signals are unavailable or unreliable
Solution Approach 1:
The system pre-calculates and stores timing offsets between GNSS time and network time before GNSS signal failure occurs. When GNSS becomes unavailable, the UE can immediately switch to using the pre-stored timing offset with network time, avoiding service interruption and maintaining synchronization reliability without sacrificing accuracy
Solution Approach 2:
Network time serves as an intermediary synchronization source when GNSS is unavailable. The patent introduces a timing offset mechanism that mediates between network time and the required V2V synchronization timing, allowing the system to maintain accurate timing through the intermediary network time source rather than failing completely without direct GNSS signals
2Adaptability or versatility
If advanced synchronization features like SIB-21 are implemented, then synchronization capability is improved, but device complexity and network upgrade requirements increase
Solution Approach 1:
The patent makes the existing SIB-20 timing offset information serve multiple functions: it provides both the primary timing offset for normal operation and acts as a fallback synchronization source when GNSS fails. This multi-functionality eliminates the need for separate SIB-21 implementation while maintaining comprehensive synchronization capability across different operating conditions
Solution Approach 2:
The system uses its own existing timing offset information stored in SIB-20 to serve itself during GNSS failure conditions, rather than requiring external network upgrades or additional complex synchronization infrastructure. The UE autonomously switches to using the pre-stored timing offset, making the system self-sufficient and avoiding increased device or network complexity
Data Source
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AI summary
A method for communication includes obtaining a timing signal from a timing synchronization reference source, computing a system frame number (SFN) direct frame number (DFN) offset, creating a timing fingerprint using the timing signal and the SFN-DFN offset, the timing fingerprint also comprising additional timing information, entering the timing fingerprint into a database, continually updating the timing fingerprint, determining whether the timing signal remains within a threshold, if the timing signal exceeds the threshold, iterating the timing fingerprint, verifying the timing fingerprint to determine whether there is a timing inconsistency between a most recent timing fingerprint and current time, if the timing fingerprint is verified, using the SFN-DFN offset to derive current DFN timing to decode a sidelink control information (SCI) communication, and if the SCI communication is decoded, using the timing signal for communicating over a sidelink communication channel.