GNSS-Based V2X Synchronization Module for Base Station Independent Timing
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Solution Overview
Problem
Current cellular vehicle-to-vehicle (V2V) communication systems, as per 3GPP standards, fail to meet National Highway and Transportation Safety Agency (NHTSA) requirements for clock synchronization and privacy protection, leading to incompatibility with US road regulations and increased implementation costs.
Innovation Solution
A geolocation-based synchronization module within the vehicle's Telematic Control Unit (TCU) uses Global Navigation Satellite System (GNSS) signals for synchronization, independent of cellular base stations and Subscriber Identity Module (SIM) authentication, allowing for secure and cost-effective V2V communication without relying on SIM-authenticated communication or base station signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If 3GPP base station signaling is used for initial synchronization, then clock synchronization is achieved with 0.2 ppm drift error, but NHTSA requirement of 0.1 ppm drift error is not met
Solution Approach 1:
The patent introduces GNSS as an intermediary synchronization source that provides timing signals with better than 0.1 ppm accuracy. The system uses GNSS-derived timing to initialize and maintain synchronization, acting as a mediator between the vehicle communication system and the cellular network, thereby achieving both the required precision and NHTSA compliance simultaneously
Solution Approach 2:
The patent changes the synchronization parameter source from base station signaling (0.2 ppm accuracy) to GNSS signals (better than 0.1 ppm accuracy). By switching the reference timing source and adjusting synchronization parameters based on GNSS data, the system achieves the required 0.1 ppm drift error threshold while maintaining continuous synchronization through hybrid methods
2Measurement precision
If base station signaling is used for synchronization, then timing synchronization is achieved, but NHTSA requirement for GNSS-only synchronization is violated
Solution Approach 1:
The patent positions GNSS as the primary intermediary for obtaining timing synchronization, requiring that initial synchronization always comes from GNSS signals. The base station signaling is used only as a secondary reference or for maintaining synchronization, not for initial timing acquisition, thereby satisfying NHTSA's GNSS-only requirement while still achieving accurate timing synchronization
Solution Approach 2:
The system performs preliminary synchronization using GNSS signals before engaging with base station signaling. The GNSS timing is established first as the reference, and any subsequent base station signaling is synchronized to this GNSS-derived timing, ensuring that the fundamental NHTSA requirement of GNSS-based synchronization is met from the outset
3Measurement precision
If SIM/USIM is used for system synchronization, then initial communication synchronization is achieved, but hardware and software design complexity increases
Solution Approach 1:
The patent extracts the synchronization function from the SIM/USIM subsystem and relocates it to the GNSS receiver and application processor. By separating the timing synchronization function from the cellular authentication module, the system achieves initial communication synchronization without requiring complex integration between SIM/USIM and the C-V2V communication stack, thereby reducing hardware and software design complexity
Solution Approach 2:
The patent introduces GNSS as an intermediary that provides timing information directly to the C-V2V communication system without requiring SIM/USIM involvement. This intermediary approach eliminates the need for complex data paths and access mechanisms between SIM/USIM and the communication module, simplifying the overall system architecture while maintaining synchronization accuracy
4Measurement precision
If SIM/USIM access is used for synchronization, then timing information is obtained, but driver anonymity and security are compromised
Solution Approach 1:
The patent extracts the timing information acquisition function from the SIM/USIM and relocates it to the GNSS receiver. By obtaining timing data directly from GNSS signals rather than through SIM/USIM access, the system eliminates the security risk of continuous SIM access while maintaining the ability to obtain precise timing information for communication synchronization
Solution Approach 2:
The patent uses GNSS as an intermediary source for timing information that does not require access to personally identifiable information stored in the SIM/USIM. This intermediary approach provides the necessary timing data for synchronization while preserving driver anonymity and eliminating security concerns associated with continuous SIM access
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures compliance with NHTSA mandates by providing precise timing synchronization and maintaining driver anonymity, while reducing implementation expenses and carrier charges for frequent V2V communications.
Implementation Method 1
A geolocation-based synchronization module within the vehicle's Telematic Control Unit (TCU) uses Global Navigation Satellite System (GNSS) signals for synchronization
Data Source
AI summary
A cellular vehicle-to-everything (C-V2X) [including V2V] communication system obtains location and time data from one or more GNSS signals and retrieves cellular synchronization information (including but not limited to 3GPP MIP and/or SIB) from a pre-loaded database and uses the information to establish a C-V2V connection with another vehicle. Synchronization may be repeated after expiration of a time period. The time period may be selected according to a location and velocity of the vehicle. Other sources of time data may be used when GNSS signals are not available, such as an internal crystal clock or timing from a cellular base station.