Page 321 - Integrated Wireless Propagation Models

I
I n - B u i I d i n g ( P i c o c e I ) P r e d i c t i o n M o d e I s 299
This model applies only to conventional office buildings, which are not odd shaped or
attached to other unmatched buildings. We have shown that the RP building in Singapore
(Sec. 5.3.2.2.1) is not a conventional building; thus, the data collected from the RP build­
ing have different characteristics.

A. The Lee Empirical Model for lnterfloors The path loss L due to the interfloor case when
i-f
the transmitter and the receiver are in the different floors can be expressed as follows:
For the path loss between any two floors at first seven floors (six-floor separation),
the interfloor loss L' goes linearly as the loss per floor for every floor.
i-f
· n + L,_
L' = m 11 t:.1 1 (5.3.2.2.2.1)
i1
where m is the loss per floor, n is the number of floor separations, L,_ is the loss
11
1
t:.f
received at the receiver when it is on the same floor as the transmitter and is located
either-lose to the floor I ceiling or to the floor I ground, and m is a function of frequency.
11
From the empirical data, we can express it as
m = 1 . 93 f cHz + 6.36 (5.3.2.2.2.2)
fl
At 850 MHz, m = 8 dB/floor, and L,_ = 10 dB (from Fig. 5.3.2.2.2.1).
11
1
L' = 8 · n + 10 (5.3.2.2.2.3)
t:.f
i1
At 2.3 GHz, m = 10.8 dB/floor, and L, = 10 dB (from Fig. 5.3.2.2.2.1)
11
-f
in dB (5.3.2.2.2.4)
From the measured data, we discovered that after the first six-floor separations, the
interfloor loss L" _ is no longer linear but follows the logarithm scale:
i1
in dB (5.3.2.2.2.5)
where m is the loss slope per six floors on a logarithm scale; that is, the loss of the first
12
six-floor separations is 10 dB, the loss of next 12 floor separations is 10 dB, the loss of the
next 20 four-floor separations is 10 dB, and so on. The general path-loss slope of m is
12
the exponent doubled over a given number of floor separations and can be expressed as
m = fl llog 2 in dB (5.3.2.2.2.6)
2
12
where fl is the path loss over a given number of floor separations as a transition at this
2
separation for different loss slopes. In our case, the number of floor separations is six,
and fl is 10 db. Thus, the path-loss slope from the first six-floor separations to that after
2
the six-floor separation are different, and the transition is at the six-floor separations.
2
A is the constant that makes two interfloor loss curves, Eq. (5.3.2.2. . 1 ) and
Eq. (5.3.2.2.2.5), to be connected at a given floor separation as shown in Fig. 5.3.2.2.2.1.
The constant A can be found by setting two equations equal to n = 6, that is,
t:.f
six-floor separation.
(5.3.2.2.2.7)
where a is the correction factor in dB value added when the measured data show the
difference between two slopes at the transition.
From the measured data collected at 900 MHz or lower, the two path-loss slopes are
not continuous at the transition, which is six-floor separations. There is a 5-dB-less loss