Underground Communication: Radio Propagation Prediction for CBTC Data Communication Subsystem Design

The radio-based data communication subsystem (DCS) between trains and wayside is a key factor for safe and efficient operation of a communication-based train control (CBTC) system. The train control system is now able to provide efficient, flexible, and cost-effective operation by using cutting-edge information and communication technologies collectively referred to as CBTC. CBTC technology has become standardized, and its commercialization trend has witnessed a drastic growth in recent years [1], [2]. CBTC systems are able to ensure safety and promote railroad transportation capacity and operational flexibility through continuous bilateral communication between the wayside and the moving vehicle. The cited communication is established through the DCS based on wired and/or wireless media [3], [4]. The radio-based DCS is an integrated seamless Ethernet-Internet Protocol network that includes both wire-lined and wireless components. Providing adequate radio-frequency (RF) coverage in the operational frequency band, which is normally composed of the upper ultrahigh frequency (UHF)/lower superhigh frequency (SHF), throughout the service area is the foundation for delivering uninterrupted wireless communication and, as such, a design requirement for the DCS.