Future 5G-oriented system for urban rail transit: Opportunities and challenges

As a development direction of urban rail transit system, the train autonomous circumambulate system (TACS) can operate in a safer, more efficient, and more economical mode. However, most urban rail transit systems transmit signals through industrial, scientific, and medical (ISM) frequency bands or narrow frequency bands, which cannot meet the requirements of TACS. As a promising solution, the 5th generation (5G) mobile communication provides more services for the future urban rail transit systems, and covers the shortages of exiting communication technologies in terms of capacity and reliability. In this paper, we first briefly review the research status of current train control system and introduce its limitations. Next, we propose a novel network architecture, and present new technologies and requirements of the proposed architecture for TACS. Some potential challenges are then discussed to give insights for further research of TACS.