Off-Network Communications For Future Railway Mobile Communication Systems: Challenges and Opportunities

TL;DR

This paper analyzes off-network communication needs for future railway systems, reviews existing technologies, and evaluates LTE-V2X and NR-V2X as promising solutions to meet strict requirements.

Contribution

It provides a comprehensive analysis of off-network use cases in FRMCS and evaluates existing communication technologies for future railway applications.

Findings

LTE-V2X and NR-V2X can meet off-network communication requirements with enhancements.

Simulation shows potential of LTE-V2X and NR-V2X for railway off-network scenarios.

Highlights the need for standardization in off-network railway communications.

Abstract

GSM-R is predicted to be obsoleted by 2030, and a suitable successor is needed. Defined by the International Union of Railways (UIC), the Future Railway Mobile Communication System (FRMCS) contains many future use cases with strict requirements. These use cases should ensure regular communication not only in network coverage but also uncovered scenarios. There is still a lack of standards on off-network communication in FRMCS, so this article focuses on off-network communication and intends to provide reference and direction for standardization. We first provide a comprehensive summary and analysis of off-network use cases in FRMCS. Then we give an overview of existing technologies (GSM-R, TETRA, DMR, LTE-V2X, and NR-V2X) that may support off-network communication. In addition, we simulate and evaluate the performance of existing technologies. Simulation results show that it is possible to satisfy the off-network communication requirements in FRMCS with enhancements based on LTE-V2X or NR-V2X. Finally, we give some future research directions to provide insights for industry and academia.