MPC-based time synchronization method for V2V (vehicle-to-vehicle) communication

Abstract

PurposeAs the strategy of 5G new infrastructure is deployed and advanced, 5G-R becomes the primary technical system for future mobile communication of China’s railway. V2V communication is also an important application scenario of 5G communication systems on high-speed railways, so time synchronization between vehicles is critical for train control systems to be real-time and safe. How to improve the time synchronization performance in V2V communication is crucial to ensure the operational safety and efficiency of high-speed railways.Design/methodology/approachThis paper proposed a time synchronization method based on model predictive control (MPC) for V2V communication. Firstly, a synchronous clock for V2V communication was modeled based on the fifth generation mobile communication-railway (5G-R) system. Secondly, an observation equation was introduced according to the phase and frequency offsets between synchronous clocks of two adjacent vehicles to construct an MPC-based space model of clock states of the adjacent vehicles. Finally, the optimal clock offset was solved through multistep prediction, rolling optimization and other control methods, and time synchronization in different V2V communication scenarios based on the 5G-R system was realized through negative feedback correction.FindingsThe results of simulation tests conducted with and without a repeater, respectively, show that the proposed method can realize time synchronization of V2V communication in both scenarios. Compared with other methods, the proposed method has faster convergence speed and higher synchronization precision regardless of whether there is a repeater or not.Originality/valueThis paper proposed an MPC-based time synchronization method for V2V communication under 5G-R. Through the construction of MPC controllers for clocks of adjacent vehicles, time synchronization was realized for V2V communication under 5G-R by using control means such as multistep prediction, rolling optimization, and feedback correction. In view of the problems of low synchronization precision and slow convergence speed caused by packet loss with existing synchronization methods, the observer equation was introduced to estimate the clock state of the adjacent vehicles in case of packet loss, which reduces the impact of clock error caused by packet loss in the synchronization process and improves the synchronization precision of V2V communication. The research results provide some theoretical references for V2V synchronous wireless communication under 5G-R technology.

An Overview of Current Challenges and Emerging Technologies to Facilitate Increased Energy Efficiency, Safety, and Sustainability of Railway Transport

“…According to [121], this concept can also be used for the dynamic coupling and decoupling of individual freight wagons and should notably improve the railway system capacity and throughput under varying freight transport demand. A comparative analysis of direct and indirect V2V communication between trains using fifth generation radio networks for railways (5G-R) for the purpose of platooning was presented in [122], wherein direct communication, although faster, requires additional means of synchronisation due to the absence of a central clock on the fixed communications node (repeater). The results in [122] also indicate that using advanced communications characterised by low latency can facilitate the high-precision synchronisation of train speeds and mutual distance within a platooning configuration.…”

“…A comparative analysis of direct and indirect V2V communication between trains using fifth generation radio networks for railways (5G-R) for the purpose of platooning was presented in [122], wherein direct communication, although faster, requires additional means of synchronisation due to the absence of a central clock on the fixed communications node (repeater). The results in [122] also indicate that using advanced communications characterised by low latency can facilitate the high-precision synchronisation of train speeds and mutual distance within a platooning configuration. The introduction of nonlinear train dynamics and motion resistances due to track gradient and curvature, as well as the locomotive power limitations and safety constraints at junctions into the rail traffic model based on high-bandwidth communication for the precise position and speed of the trains, may lead to significant reductions in headways, thus improving the railway system's capacity and throughput [123].…”

Effectiveness of Vehicular Communication Using NP-CSMA with Bernoulli-Based Gaussian Interpolation Function

“…Active safety systems can avoid many accidents that could otherwise occur today due to drivers' decision-making. For such active and preventative systems to operate successfully, each vehicle needs to know the locations and motions of its neighboring cars [1]- [6].…”