Measurements and Analysis of Large-Scale Fading Characteristics in Curved Subway Tunnels at 920 MHz, 2400 MHz, and 5705 MHz

Abstract

Abstract-Wave propagation characteristics in curved tunnels are of importance for designing reliable communications in subway systems. This paper presents the extensive propagation measurements conducted in two typical types of subway tunnelstraditional arched "Type I" tunnel and modern arched "Type II" tunnel-with 300-and 500-m radii of curvature with different configurations-horizontal and vertical polarizations at 920,2400, and 5705 MHz, respectively. Based on the measurements, statistical metrics of propagation loss and shadow fading (path-loss exponent, shadow fading distribution, autocorrelation, and crosscorrelation) in all the measurement cases are extracted. Then, the large-scale fading characteristics in the curved subway tunnels are compared with the cases of road and railway tunnels, the other main rail traffic scenarios, and some "typical" scenarios to give a comprehensive insight into the propagation in various scenarios where the intelligent transportation systems are deployed. Moreover, for each of the large-scale fading parameters, extensive analysis and discussions are made to reflect the physical laws behind the observations. The quantitative results and findings are useful to realize intelligent transportation systems in the subway system.

On the Feasibility of High Speed Railway mmWave Channels in Tunnel Scenario

“…is conventionally modeled as a log-normal distribution [14,36] which is confirmed in this study. Figure 9 describes the probability density function (PDF) of shadowing fading in Direc.-Direc.…”

“…Figure 3(a) illustrated that the cross section of tunnel includes the accurate dimension and the locations of TX1 and RX1. According to realistic "Type II" tunnel described in [14], the arched tunnel in this study is with dimension 8.41 m × 6.87 m ( tunnel × tunnel , where tunnel and tunnel are defined as maximum width and height of the tunnel, resp.). The heights of TX1 and RX1 are 6.5 m and 3 m, respectively.…”

Channel Measurement and Modeling in Complex Environments

“…It is worth noting that propagation at 5.7 GHz experienced less attenuation than at 2.4 GHz. A similar conclusion can be found in [211].…”

“…Thus the propagation is partially affected by waveguiding. As waveguide theory shows, waves at higher frequencies experiences smaller propagation loss [211]. Thus, n is larger at 2.4 GHz than at 5.7 GHz.…”

“…Propagation inside small vehicles include bus with passengers [205]; elevator shafts [206] and cars [207,208] have been characterized. Also, propagation properties in other confined environment such as rooms, corridors [209], and tunnels [210,211,212] have been summarized and compared. In these settings, researchers concluded that PLE values vary between 2 and 3 in the airplanes with medium to large size.…”