Channel Model for Train to Train Communication Using the 400 MHz Band

Abstract

Abstract-This paper presents a channel model for direct trainto-train communication appropriate for the 400 MHz band. Extrapolation of theoretical and experimental results obtained for the planning of other railway communication systems like GSM-R is not obvious due to the difference in frequencies, antenna height and absence of base stations. In this paper, the analysis of the channel model covers different radio phenomena including path loss, Doppler, fading, and delay spread. Concretely we consider three scenarios (train stations, shunting yards and regional networks), for which the propagation channel characteristics are discussed. Furthermore, influence of special railway environments like cuttings which can be found near cities and towns, tunnels and bridges are encountered.

A Measurement-Based Stochastic Model for High-Speed Railway Channels

“…When the train is far from the BS, the gain turns to be smaller compared with the maximum gain. This leads to a smaller evaluated path loss with (19) at large distance and, thus, results in a smaller path loss exponent in (22). This comparison shows that using a fixed antenna gain to develop the path loss model of the propagation channel, as in [5] and [11], would lead to an overestimation of the realistic path loss.…”

“…We thus use (19) to obtain modified path loss values that are then evaluated in a similar manner as before. We stress here that this compensation method is only approximate for three reasons.…”

“…Extensions to frequencies other than this band could build on the work reported in [25] and [45], which quantify an increase in path loss with the carrier frequency and cover a frequency band from 150 MHz to 6 GHz. A more detailed channel model at 2.35 GHz can be found in [20] and [21], and a train-to-train channel model at 400 MHz can be found in [18] and [19]. 2) Antenna: Since we use a very particular directional BS antenna in the measurements, there would be some errors if our radio channel model is directly used for a system with different antenna patterns.…”

“…In [17], a channel model for railways at 320 MHz is developed based on the field strength measurements in nine different cells in the rural eastern part of India. In [18] and [19], a train-to-train channel model at 400 MHz is developed for train collision avoidance. Some measurements have been conducted at a higher frequency, e.g., 2.4 GHz, which are relevant for offering broadband wireless access to passengers on HSRs.…”

A location-based MAC protocol for safety-of-life vehicle-to-vehicle communication

“…This step completed we will investigate in detail the physical layer. Having already examined the channel model [11], we will have to apply these insights into our system and verify them by simulations and tests.…”