Uplink Design of Millimeter-Wave Mobile Communication Systems for High-Speed Trains

Passengers in a high-speed train (350 km/h) experience very poor multimedia services and discontinuous connections due to the much more and simultaneous handovers in the cellular networks. To handle these problems, a millimeter-wave mobile communication system for high-speed trains was introduced and its downlink structure was presented. This paper proposes the uplink structure appropriate to the millimeter-wave mobile communication system. It also describes the frame structure, the multiple access method, and the pilot deployment of the uplink channel. Especially, the uplink pilot was designed to solve the Doppler problem in order to achieve a higher spectrum efficiency. The simulation results of the uplink channel show the spectral efficiency of 4.18 bps/Hz even in 400 km/h under the Rician fading channel conditions.