Channel characteristics in tunnels: FDTD simulations and measurement

Abstract

This paper presents the results of measurements and simulations of the characteristics of 900 MHz band radio propagation channels in a tunnel environment. The simulations were made using the FDTD method (with companion UPML) and measurements made use of the swept frequency technique. Another method, the metaheuristic Simulated Annealing, was implemented for estimating the values of characteristic parameters of materials. The FDTD code was reformulated for use with CUDA with the objective of decreasing program running time.

A Domain-Decomposition-Based Surface Integral Equation Simulator for Characterizing EM Wave Propagation in Mine Environments

“…Here inc a V is the discretized tested incident field on a Ω due to impressed sources in a Ω . The currents of interest and hence the fields inside Ω can be obtained by (i) solving (10) and obtaining other generalized impedance matrices, (ii) solving inter-domain system (8), and (iii) solving ( 11) and ( 12) as well as currents on other subdomains.…”

“…Simulators leveraging full-wave techniques (e.g. finite difference time domain [9][10][11][12] and surface integral equation (SIE) [13][14][15][16] methods) allow for high-fidelity modeling of realistic mining environments but often require excessive computational resources. Recently, a fast multipole method -fast Fourier transform (FMM-FFT) accelerated SIE simulator was developed to alleviate this computational burden [15,16].…”

Artificial neural network models for radiowave propagation in tunnels

“…For radio propagation in tunnels, analytical models based on waveguide mode theory [8] were first used. These models were complemented over the years by methods based on full-wave techniques, such as the finite difference time domain technique [9,10], on ray-tracing [11,12] or by using VPE-based models [13]. Hybrid techniques attempting to combine the advantages of the above-mentioned techniques have also been utilised [14,15].…”

An FMM-FFT Accelerated SIE Simulator for Analyzing EM Wave Propagation in Mine Environments Loaded With Conductors

“…The above-referenced techniques typically only apply to EM characterization in restricted frequency bands and do not readily account for the presence of conductors and miners, wall roughness (especially when comparable to the wavelength), or unstructured debris. Full-wave techniques for analyzing EM wave propagation in mine environments include finite difference time domain [10]–[14] and surface integral equation (SIE) methods [15]. In principle, these techniques permit faithful modeling of EM wave propagation in real-world mine environments.…”

“…In principle, these techniques permit faithful modeling of EM wave propagation in real-world mine environments. However, in practice, due to their high-computational requirements, their applicability is limited to the study of EM wave propagation in electrically small or moderately sized tunnels even when they are implemented on graphics processing units [10]. …”