3.6.2 Hata Path Loss Model
The Hata model is a mathematical representation of extensive field measurements conducted by
Okumura in Japan [96]. He provides attenuation curves relative to the propagation path loss in free
space. The measurements were made for frequencies in the range of 150 MHz to 1.9 GHz and for
transmit-receive distances between 1??“100 km. Hence to use this model the free space path loss is first
created and then an adjustment parameter is added a( f, d) to consider the relative offsets and lastly a terrain
parameter is added, GTerr, to take into account the type of terrain. The Okumura model is given as
(3.60)
Plots of the above correction factors are given in [96].
Okumura also found relationships of the BS antenna height and of the MS antenna height.
Specifically the BS varies at a rate of 20 dB/decade and the MS varies at a rate of 10 db/decade. Now
the complete model is given as
(3.61)
where the above antenna height gains are represented as
(3.62)
(3.63)
Now that we have presented the baseline data, we can now begin our discussion on the Hata model
[97]. The Hata model is based on the Okumura measurements. The model starts with average path
loss in the urban environment and then adjustment factors are added for other environments.
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