Performance Evaluation of mmWave in 5G Train Communications

Seamless broadband connectivity and high data rates are a prerequisite for 5G networks, especially for connectivity to moving platforms. The H2020 5G-PICTURE project considers a complete network solution that supports operational and end-user services, for both Information and Communications Technology and vertical industries such as 5G rail. Targeting wireless access communication to High Speed Trains (HST), this paper presents an overview of both LTE-A and millimeter-Wave (mmWave) solutions. Moreover, we present a performance evaluation, considering a train, equipped with two mmWave antennas (front and rear), traveling along two 1.4km rail tracks, with several mmWave Access Points (APs) placed at the trackside. With the aid of a ray-tracing tool, to obtain realistic channels, and an IEEE 802.11ad simulator, assuming receive diversity, we investigate the impact of beamforming, frequency band (26GHz and 60GHz) and cell radius on the achievable throughput. Based on our results, the employment of beamforming considerably increases the system's throughput. Moreover, we show that even when APs on the trackside are placed 800m apart, the coverage is almost seamless. Finally, investigating the angular profile of each beam, we suggest a beamwidth of 20° to maintain connection to a distance greater than 30m from the APs, for the considered scenarios.