Path Loss Models for Train-to-Train Communications in Typical High Speed Railway Environments

Within the next decades railways will undergo a major modernization in Order to increase their efficiency and safety. The modernization process will enable new concepts such as fully autonomous trains and dynamic coupling of consists. Today's centralized railway management systems will not be able to safely handle these train concepts and, thus, will be replaced or complemented by new systems. These systems require a tight train monitoring which is based on the reliable exchange of information covering among other the accurate position and velocity of trains. We are sure that modern train concepts demand both reliable train-totrain (T2T) communication and improved capabilities for train-to-ground (T2G) communication. However, T2T communication is hardly investigated and so far no technology has been selected. With this publication we like to provide more insight into T2T signal propagation. This is the basis for the future development of a modern T2T communication system. We focus on wide band propagation for T2T scenarios and describe an extensive channel sounding measurement campaign involving two high speed train (HST)s. Results on signal propagation measurements in high speed T2T scenarios are presented for different environments. Hence, path loss models for rural, sub-urban and tunnel environments are introduced