WDM RoF-MMW and Linearly Located Distributed Antenna System for Future High-Speed Railway Communications

In this article, we propose dual-hop network architecture capable of providing high-speed communications to high-speed trains (HSTs). The system uses a seamless fiber-millimeter-wave system for backhaul transmission from a central station to antennas on trains, and a highspeed in-train Wi-Fi network. The system can be combined with signal processing and network control technologies to compensate for interference and the Doppler effect, and to reduce the number of handovers. It can realize seamless connectivity between the inside and outside of trains to avoid penetration loss and help organize the in-train network optimally to increase coverage and data rate. We present and discuss the possible network architecture and technologies that can help realize the proposed network. We also present a proof-of-concept demonstration on a high-performance seamless fiber-MMW system that can be applied for applications in backhaul networks. The proposed network can be an attractive solution to provide broadband services such as video on demand and high-speed mobile signals to users on HSTs.