High-Speed Train Communications Standardization in 3GPP 5G NR

In 3GPP New Radio (NR), high-speed train (HST) is considered as one of the essential verticals in 5G applications. In this article, architectures and applications of 5G network slicing to HST are described. In addition, both higher layer and physical layer technologies are proposed to improve the quality of train communication in a 5G system. End-to-end network slicing that penetrates both the core network and radio access network can meet various performance requirements for 5G HST use cases, thanks to the flexibility offered by the proposed technologies. The higher layer technologies proposed in this article cover initial access, mobility management, and linear cell designs. Following the descriptions of evaluation parameters for the HST scenario adopted in 3GPP, the proposed physical layer technologies for HST applications including numerology and reference signal designs are explained. Link-level evaluation results are shown to demonstrate the superior performance of the proposed methods.