V2X Synchronization Using Joint LTE and GNSS Timing References
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current LTE-based V2X synchronization methods face challenges in providing reliable and accurate synchronization, especially in out-of-coverage scenarios, due to inadequate frequency accuracy and stability of UE oscillators, leading to unstable system behavior and frequent re-synchronization issues.
Innovation Solution
The integration of joint cellular (LTE or UMTS) and GNSS technologies to provide a ubiquitous and seamless synchronization solution for LTE-based V2X services, utilizing GNSS timing references to discipline local oscillators and propagate synchronization signals, along with network-based synchronization assistance to ensure accurate and stable timing across various coverage scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UE oscillators are used for synchronization in out-of-coverage scenarios, then device autonomy is improved, but frequency accuracy and stability deteriorate
Solution Approach 1:
The system dynamically adjusts synchronization behavior based on coverage status and oscillator quality. In out-of-coverage scenarios, UEs transition from network-synchronized mode to autonomous oscillator-based mode, adapting their synchronization source according to environmental conditions and available references.
Solution Approach 2:
The patent changes the synchronization parameter source from network-provided references to locally-generated oscillator references when out-of-coverage is detected. This parameter change involves switching the timing reference source and adjusting synchronization tolerances based on oscillator quality metrics.
2Adaptability or versatility
If UE oscillators are used for synchronization, then operation out of coverage is enabled, but system stability deteriorates
Solution Approach 1:
The system prepares for out-of-coverage operation by pre-characterizing oscillator quality metrics and pre-establishing synchronization parameters. Before transitioning to autonomous mode, the system accumulates oscillator performance data and configures appropriate synchronization tolerances to cushion against potential instability.
Solution Approach 2:
The patent implements feedback mechanisms where UEs monitor their oscillator performance and synchronization accuracy, then adjust their behavior accordingly. This feedback loop helps maintain system stability by detecting drift and triggering re-synchronization or parameter adjustments when necessary.
3Measurement precision
If multiple synchronization sources are integrated, then synchronization accuracy is improved, but device complexity increases
Solution Approach 1:
The system introduces an intermediary synchronization selection mechanism that mediates between multiple references (network references, GNSS, and local oscillators). This intermediary layer selects and prioritizes synchronization sources based on availability and quality, simplifying the overall system architecture while maintaining multiple reference options.
Solution Approach 2:
The patent creates a universal synchronization framework that can operate with multiple different reference sources through a common selection and prioritization mechanism. This multi-functional approach allows the same device to use different synchronization sources (network, GNSS, oscillators) depending on the operational scenario, reducing the need for separate specialized systems.
Data Source
AI summary
Cellular (e.g., LTE or UMTS) and global navigation satellite system (GNSS) based technologies can provide ubiquitous and seamless synchronization solution for LTE-based vehicle to everything (V2X) or Proximity Services synchronization (ProSe) services. For example, by using joint GNSS timing references and LTE cellular network timing references for V2X or ProSe system synchronization benefits of using GNSS technologies to improve synchronization procedure for LTE based V2X or ProSe services can be enabled, including: (1) accurate and stable timing, (2) availability of a global and stable timing reference and (3) ability to propagate GNSS timing by user equipment having sufficient GNSS signal quality.