Browsing by Author "Ju, KM"

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A novel 3-D scattering model of 1.8-GHz radio propagation in microcellular urban environment
(1999-05-01)
Tarng, JH
;
Ju, KM
;
電信工程研究所
;
Institute of Communications Engineering
This work presents a novel three-dimensional (3-D) scattering model to predict the path loss of a microcellular radio channel in an urban environment. The analytical scattering model combined with a patched-wall model predicts the median path loss more accurately than the conventional analytical ray-tracing model in the cases studied, Comparing the path loss with the measured one at 1.8 GHz demonstrates the effectiveness of the scattering model. The scattering model includes three major propagation modes: 1) a direct-path wave; 2) a ground-reflected wave; and 3) the scattered field from the walls aligned along a street. The proposed model with a polarization scattering matrix associated with the patched-wall model aptly describes the third mode, which is usually neglected or oversimplified.
Measurements and modeling of radio propagation in large offices with low metallic partitions
(1996-06-20)
Ju, KM
;
Tarng, JH
;
電信工程研究所
;
Institute of Communications Engineering
A theoretical model is developed to predict the propagation loss of UHF radio waves in large modem offices with low metallic partitions. It is found that in addition to free-space propagation loss the shadowing loss due to the blockage by the low partitions in the out-of-sight situation becomes the dominant one. The shadowing loss can be efficiently formulated by using the theory of single or double knife-edge diffraction. The model has been verified by an experiment conducted at 905 MHz, 1.75 GHz, and 2.44 GHz in large offices. The model shows reasonable accuracy. (C) 1996 John Wiley & Sons, Inc.
Measurements and modeling of radio propagation in large offices with low metallic partitions
(1996-06-20)
Ju, KM
;
Tarng, JH
;
交大名義發表
;
電信工程研究所
;
National Chiao Tung University
A theoretical model is developed to predict the propagation loss of UHF radio waves in large modem offices with low metallic partitions. It is found that in addition to free-space propagation loss the shadowing loss due to the blockage by the low partitions in the out-of-sight situation becomes the dominant one. The shadowing loss can be efficiently formulated by using the theory of single or double knife-edge diffraction. The model has been verified by an experiment conducted at 905 MHz, 1.75 GHz, and 2.44 GHz in large offices. The model shows reasonable accuracy. (C) 1996 John Wiley & Sons, Inc.
Statistical distributions of Rician factor for radio LOS propagation in urban microcells
(1998-06-01)
Tarng, JW
;
Ju, KM
;
電信工程研究所
;
Institute of Communications Engineering
The Rician factor is an important parameter in evaluating the outage probability and reuse distance of cellular systems. From the measurement of 1.8 GHz radio propagation in outdoor urban microcells, it is found that the measured pdf of the Rician factor for low tier systems follows a lognormal distribution and the factor is independent on the propagation distance.