5G for Railways: Next Generation Railway Dedicated Communications

To overcome increasing traffic, provide various new services, further ensure safety and security, and significantly improve travel comfort, a new communication system for railways is required. Since 2019, public networks have been evolving to fifth generation (5G) communication worldwide, whereas the main railway communication system is still based on second generation (2G) communication. It is thus necessary for railways to replace the current 2G-based technology with the next generation railway dedicated communication system with improved capacity and capability, and the 5G for railways (5G-R) technology is a promising solution for further intelligent railways. This article gives a review of the current developments of next generation railway communications, followed by a discussion of the typical services that 5G-R can provide to intelligent railways. Then the main application scenarios of 5G-R are summarized, and system configurations are compared. Some key technologies of 5G-R such as network architecture, massive MIMO, millimeter-wave, multiple access scheme, and ultra-reliable low-latency communication are presented and analyzed. Finally, some challenges of 5G-R are highlighted.