Non Line-of-Sight Microwave Propagation Characterization for Personal Communications with High-Tier Base Station Antenna

Kozo SAKAWA  Hironari MASUI  Masanori ISHII  Hiroyuki SHIMIZU  Takehiko KOBAYASHI  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E85-A   No.7   pp.1569-1577
Publication Date: 2002/07/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Multi-dimensional Mobile Information Networks)
Category: 
Keyword: 
microwave propagation,  non line-of-sight,  high-tier base station,  path loss,  relative loss,  

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Summary: 
We have measured the non line-of-sight (NLOS) propagation characteristics of microwave frequencies in an urban environment with a base station antenna situated well above the surrounding buildings. When these characteristics are compared with the results of measurements made in the same environment with a low base station antenna height, it can be seen that with a low base station antenna height the attenuation coefficient varies greatly between line-of-sight (LOS) and NLOS environments, whereas with a high base station antenna height there is no variation of this sort. This is because the waves arriving NLOS environments from a high base station antenna do so primarily as a result of rooftop diffraction, and the path loss does not vary much over regions of equal distance between the base station and mobile station. We have confirmed that the frequency characteristics of relative loss in NLOS environments with a high antenna height follow a relationship of 22.8 log f, which is more or less the same as the characteristic for the UHF band. By modifying the frequency terms of the Sakagami model (used for UHF band) based on this trend to allow it to handle microwave frequencies, a close correspondence is seen between the results of actual measurements and the values predicted by the extended model.