High Speed Train Communications in 5G: Design Elements to Mitigate the Impact of Very High Mobility

Abstract

5G wireless technology is expected to provide much improved performance in terms of data rate, reliability, latency, and mobility in various use cases and deployment scenarios. One of these promising 5G deployment scenarios is the high speed train scenario, which aims to offer broadband access to passengers on a high speed train running up to 500 km/h. Such very high mobility imposes considerable technical challenges to be dealt with during the 5G standardization phases. This article introduces the technical specifications of 5G NR with particular attention on the high speed train scenario. Based on the concrete high speed train scenario description, various NR design elements to achieve such very high mobility are discussed including numerology, frame structure, reference signals, multi-antenna schemes, cell search, random access, and mobility support. Discussions on the challenges and perspectives for high speed train communications of Beyond 5G are also provided.