Exploring the Potential and Feasibility of Time Synchronization using GNSS Receivers in Vehicleto-Vehicle Communications
Khondokar Fida Hasan, Yanming Feng, and Yu-Chu Tian, School of Electrical Engineering and Computer Science, Queensland University of Technology, Australia
Location: Regency B
Date/Time: Wednesday, Jan. 31, 11:00 a.m.
Time synchronization is a prerequisite establishment for the successful operation of every distributed network systems. Generally, synchronization ensures secure connectivity, data consistency and process coordination among the nodes of the network system. In vehicle-to-vehicle and vehicle-to-infrastructure communications, the network nodes are moving rapidly and formed in ad hoc manner. For safety application, the requirement for delay, reliability, scalability, fairness, and timeliness of V2X communications is stringent. For instance, the update rate of vehicle location information can be as high as 10-100Hz. The requirements for absolute and relative vehicle positioning accuracy can be as high as 10 centimeters. These have been reasonably well understood. However, the requirements for time synchronization in V2X communications or how precise time solutions can benefit V2V communications and safety applications are less studied. GNSS has been used for providing precise timing information in many distributed systems. Therefore, integration of GNSS-based time synchronization in-vehicle networks can be a promising technological solution for the better coordination of the emerging automated and connected vehicles. In this research work, we identified the importance and application scenarios of GNSS precise time transfer and relative time synchronization for V2X communications. A review of synchronization impairments over vehicle networks and the state-of-the-art mechanisms to improve the synchronization accuracy is then presented. In compared with various proposed methods of synchronization, the benefits and capabilities of GNSS timing information to synchronize vehicular network nodes is discussed. It is found that GNSS time synchronization solely can be a replacement of existing TSF based synchronization in VANET. The limitations due to GNSS time solutions outages in high-rising streets and tunnels are also analyzed with the vehicle GNSS tracking data in the Brisbane CBD area. This analysis indicates that time drift solution can be successfully handled and potential strategies can be helpful to bridge time solution outages. A following-on experiment is conducted to evaluate the timing accuracy possible using GNSS time synchronization integrating into various layers to demonstrate its compatibility and feasibility in a number of real V2V application scenarios.