Analysis of path loss and delay spread at 900 MHz and 2.1 GHz while entering tunnels

Author

Pallarés, Fernando Martí ; Juan, Francisco J Ponce ; Juan-Llácer, Leandro

Author_Institution

Dept. of Comuniciones, Univ. Politecnica de Valencia, Spain

Volume

50

Issue

3

fYear

2001

fDate

5/1/2001 12:00:00 AM

Firstpage

767

Lastpage

776

Abstract

Some propagation characteristics in tunnel environments at 900 MHz and 2.1 GHz are analyzed. Narrow-band parameters are given in terms of the propagation factor and linear regression slopes. Wide-band analysis is considered by calculating delay spread factors along the communication path. A ray-launching technique has been implemented, using ray optics and the uniform theory of diffraction (UTD). The proposed theoretical model has been validated by comparing the results with measurements obtained by other authors. The particular situation when a mobile antenna crosses the tunnel entrance and transmitter is outside the tunnel is studied. Our simulations show that the larger the angular separation of the transmitter with respect to the tunnel longitudinal axis is, the higher values of the delay spread. The more critical point appears around the tunnel entrance (“excitation zone”), where a signal power decay up to 40 dB may be detected. A similar value has been already found when turning a corner in microcellular urban environments

Keywords

UHF radio propagation; delays; geometrical theory of diffraction; losses; microcellular radio; mobile antennas; radio transmitters; 2.1 GHz; 900 MHz; LOS link; UHF; UTD; angular separation; communication path; delay spread; delay spread factors; excitation zone; linear regression slopes; measurements; microcellular urban environments; mobile antenna; narrow-band parameters; nonLOS link; path loss; propagation characteristics; propagation factor; ray optics; ray-launching technique; signal power decay; transmitter; tunnel entrance; tunnel longitudinal axis; uniform theory of diffraction; wide-band analysis; Antenna measurements; Delay; Linear regression; Mobile antennas; Mobile communication; Narrowband; Optical propagation; Optical transmitters; Physical theory of diffraction; Wideband;

fLanguage

English

Journal_Title

Vehicular Technology, IEEE Transactions on

Publisher

ieee

ISSN

0018-9545

Type

jour

DOI

10.1109/25.933311

Filename

933311