Large-Scale Propagation Characterization of 2100 MHz 5G-R in Typical Railway-Line Scenarios Based on Passive Measurements

Reliable radio coverage is essential for the deployment of 5G for railway (5G-R) communication systems in complex railway-line environments. Previous simulation- and measurement-based studies have mainly focused on main-track railway scenarios, while the propagation characteristics in railway-side obstructed environments remain insufficiently characterized. To address this gap, this paper investigates large-scale propagation characteristics using passive synchronization signal reference signal received power (SS-RSRP) measurements collected from a 5G-R test network. Typical railway-line scenarios, including open line-of-sight (LOS) propagation, building-obstructed railway-side sections, viaduct-blocked regions, and depot-like environments, are analyzed to reveal the influence of railway-side structures on large-scale signal behavior. A floating-intercept (FI) model is adopted to characterize scenario-dependent path loss, and a height-corrected FI refinement is further introduced for building-obstructed sections. The results show that local railway-side structures introduce distinct and quantifiable excess propagation loss beyond conventional distance-dependent path loss. The obtained model parameters can support large-scale propagation modeling, link-budget margin design, coverage-hole identification, and wireless coverage evaluation for 2100 MHz 5G-R systems in obstructed railway-side environments.