Page 364 - Integrated Wireless Propagation Models

342 C h a p t e r S i x

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such the ray-tracing and FDTD techniques, &- to validate its applicability, as shown in
Sec. 5.6.2.3 for the in-building environment. Results show that the Lee comprehensive
model is as good as any other model.
Also in this chapter, we introduce four different transmission media that are differ­
ent from our terrestrial mobile transmission medium. They are satellite communication
signal, underwater communication signal, aeronautical communication signal, and
bullet train communication signal. The readers can understand and compare the differ­
ences among the different media.

6.2 I n tegrating the Three Lee Models
The Lee model is based on the different types of human-made environment and the
terrain variations. Under the terrain variations, the slope and intercept are consid­
ered as the baseline. The effect of human-made constructions can be translated to a
slope of the path-loss curve. The Lee macrocell model has been implemented in
AT&T markets since 1984. However, with the fast growth of femto-, pico-, and micro­
cells, new models were needed to accurately predict the propagation in smaller and
highly impacted human-made environment. Lee has developed the micro- and pica­
cell models, which can be used in the femtocell prediction. The goal of this section is
to identify a way to integral all three models together to solve all system deployment
issues.
The generalized equation of received signal strength is expressed in Eq. (3 1 . 2.1)
.
and restated as

The Lee single-breakpoint model is derived from Eq. (3 1 . 2 . 1 ) and is composed of
.
3
four components, as shown in Sec. . 1 .2:
Signal Area-to- Effective antenna Diffraction
streng� affia pa� � / loss

) = P,0 - r · log(�) + A1 + Geffh (h9, h 2 ) + L + a

' Adjustment
factor
The causes of these components are described as follows;

1 . The area-to-area path-loss slope y is affected by the human-made environment,
such as suburban, urban, open area, metropolitan, in-building, and other
human-made construction areas.
2. The effective antenna height gain varies due to the fluctuation of terrain
contour. The effective antenna height gain varies as the mobile moves along the
mobile path. The larger the fluctuation of the terrain contour, the more rapid
the change of the effective antenna height gain.