Ray-optical prediction of radio-wave propagation characteristics in tunnel environments. 1. Theory

Abstract

REFERENCES1. D.M.J. Devasirvatham, Time delay spread measurements of wideband radio signals within a building, Electron Lett 20 (1984), 950 -951. 2. D.M.J. Devasirvatham, Time delay spread and signal level measurements of 850 MHz radio waves in building environments, IEEE Trans Antennas Propagat AP-34, pp. 1330 -1335, Nov. 1986. 3. A.A.M. Saleh and R.A. Valenzuela, A statistical model for indoor multipath propagation, IEEE J Select Areas Commun SAC-5 (1987), 138 -145. 4. D.M.J. Devasirvatham, Multipath time delay spread in the digital portable radio environment, IEEE Commun Mag 25 (1987), 13-21. 5. T.S. Rappaport, Characterization of UHF multipath radio propagation inside factory buildings, ABSTRACT: Array antennas mounted on aircraft, ships, or any other complex platform suffer from mutual coupling and coupling with the platform in the transmission or reception of electromagnetic waves. These coupling effects affect the estimation of the direction of arrival (DOA) of plane waves performed with on-board antennas. With the use of the method of moments (MoM) to model these electromagnetic (EM) coupling terms, closed-matrix expressions for the Cramer-Rao bound (CRB) are obtained for on-board array antennas considering both mutual coupling and platform coupling effects. Some significant differences in the CRB have been found when this bound is compared with the same bound calculated in an ideal free coupling environment. Numerical results are shown to illustrate these effects.ABSTRACT: General transmission-line equations based on the theory of differential equations [1] were introduced in [2] and [3]. The equations' dispersion characteristic of a microstrip low-pass filter is studied. The parameters L, C, ␣, and ␤ of general transmission-line equations are found to be almost invariant to frequency in the passband of the microstrip low-pass filter. By restoring current and voltage distributions with the use of equations in both frequency and time domains, the broadband property of these equations on the microstrip low-pass filter is evident.

Radio Wave Propagation in Arched Cross Section Tunnels – Simulations and Measurements

“…Several methods based on the ray-optical modeling approach have been proposed. They use ray launching [2], [6], the image method [7] or combination of each [1]. They all consider only the case of straight and rectangular tunnels.…”

Capacity and Outage Analysis of MIMO and Cooperative Communication Systems in Underground Tunnels

“…In the literature, there are mainly three types of models to characterize the wireless channel in empty tunnels [6]: the Geometrical Optical model (GO model) [7], [8], the Waveguide model [9], and the Full Wave model [10]. The GO model and the Full Wave model can only provide numerical results and the computational complexity is high.…”

“…The complex channel gain matrix H is a × matrix [ℎ ] × . The matrix element ℎ is the channel gain between RX antenna and TX antenna , which is given in (8). We assume that the transmitter does not have the channel state information (CSI).…”

“…In underground tunnels, the channel gain ℎ , ℎ , and ℎ can be calculated by (8). Then the instantaneous cooperative capacity in underground tunnels can be derived.…”

A Mode-Based Approach for Channel Modeling in Underground Tunnels under the Impact of Vehicular Traffic Flow

“…techniques to model the wireless channel [5], [6]: the Geometrical Optical model (GO model) [7], [8], the Waveguide model [9], [10], and the Full Wave model [11]. The GO model and the Full Wave model are limited to numerical results and may create great computational burdens.…”