Towards 5G Infrastructure - redundant Communications for Next Generation Railways

Although railways are in most cases a very safe and highly energy efficient means of transportation, the dominant mode of transportation is road transport. It accounts for 75% of all freight and 80% of all passenger transportation in EU-28. In order to shift more traffic on the railways, next generation railways need to become more attractive and competitive by realizing innovations both on the rolling stock and the railway infrastructure. For that academia and industry are researching new applications such as wireless train control and monitoring systems (TCMS), virtual coupling of trains, and autonomous trains. A key enabling technology for these new applications is wireless communications. When considering wireless communications for railways, typically we talk about train-to-ground communications for the control, monitoring, and operations of trains as well as for passenger services and devices. In the first case, GSM-R is widely used today and will be replaced by LTE-R in the near future and in the mid-term to long-term by 5G. 3GPP has started a study on the future railway mobile communication system including the use cases of virtual coupled and autonomous trains using train-to-ground communication. Similar to LTE-V2X, we propose to use direct train-to-train communication in addition to train-to-ground communication to enable wireless TCMS, virtual coupling and autonomous trains. Within this work, we present several results showing the benefits of wireless train-to-train communication for next generation railways. For example, the redundant and low latency train-to-train communication can communicate control data and simultaneously measure the distance between two virtual coupled trains. Moreover, train-to-train communication can monitor the train integrity without requiring additional spectrum resources in contrast to a radar sensor