Joint Network and Propagation Performance Evaluation for High-Speed Railway Communications in the mmWave and THz Bands

With rapid development in China and worldwide, reliable and broadband wireless communications in high-speed railway (HSR) become a stringent challenge recently. The current dedicated railway systems, GSM-R and LTE-R, cannot satisfy the demand of ultra-high data rates in the HSR communications. In this paper, a network design for mm-wave and THz wireless communications that co-exists with the dedicated systems in HSR is developed. Moreover, dynamic beamsteering including beamforming to overcome dropoffs and a soft handover protocol among neighboring mm-wave and THz base stations are presented. Furthermore, a complete propagation channel model is developed for the mm-wave and THz communications in HSR, by considering the weather influences including rain, fog, sand and dust. Numerical results show that the capacity in HSR reaches 27 Gbps at 300 GHz with the bandwidth of 50 GHz while the coverage is no more than 300 m. However, fog and heavy rain cause additional attenuations while the efforts of sand and dust are small.