Before you read this part in 3G Network Planning you should read the below Parts in first
Radius & number of sites Calculation
the radius of cell is the most important output of the dimensioning process which the whole planning process depends on its value.
to calculate the radius of cell we use a propagation model which predict the signal level of RX at the distance of interest which in this case is the cell edge .
Okumara hata model
-accurate calculation for frequency band 150-1500MHz
-Node B height 30-200 m (Hb)
-mobile height 1-10 m (Hm)
-cell range resulted in the range of 1-20 Km (R)
-the equation take the Urban area type as reference
MAPl urban= 69.55+26.16 log f -13.85 log Hb +(44.9-65.5 log Hb)log R-a(Hm)+K
for small and medium size cities
a(Hm)=(1.1log f -0.7)Hm -(1.56 log f -0.8)
for Large city with f <=300 MHz
a(Hm)=8.29(log1.54Hm)2-1.1
for Large city with f >=300 MHz
a(Hm)=3.2(log11.75Hm)2-4.97
as discussed before this model take the Urban area as a refrence so we add a factor K to naturalize this effect
K Dense urban=3dB
K urban=0dB
K Suburban=-2(logf/28)2-5.4
K rural=-4.8(logf)2+18.33 log f -40.94
COST231-Hata model :
-accurate calculation for frequency band 1500-2600MHz
-Node B height 30-200 m (Hb)
-mobile height 1-10 m (Hm)
-cell range resulted in the range of 0.2-5 Km (R)
-the equation take the Urban area type as reference
-a(Hm)&K has the same value as the previous model.
MAPl urban= 46.3+33.9 log f -13.85 log Hb +(44.9-65.5 log Hb)log R-a(Hm)+K
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Standard propagation model :
-K1=165.5 ==>>attenuation constant.
-k2=44.9 ==>> distance attenuation constant.
-k3=-2.93 ==>> MS antenna height modifying factor .
-K4=0.0 ==>> MS antenna height modifying factor .
-k5=-13.82==>> NODE B antenna height modifying factor .
-k6=-6.55 ==>> NODE B antenna height modifying factor .
-k7=-0.8 ==>> diffraction modifying factor.
-k8= 5 for dense urban,0 for Urban ,-2.5 for sub Urban , -2 for rural.
MAPl = K1+k2log R +k3 Hm+k4 log Hm +k5 log Hb+k6 log
Hb logR +k7*diffraction loss +k8
we enter the propagation model with MAPL as input which is calculated from previous step
and calculate the radius of cell .
The next step is to calculate the site area to know the number of site needed to cover the required area.
site area calculation :
the site area calculation depends on the type of antenna as we know that the main loop range will be differ as shown in figure 9 & 10
Number of site calculation :
the number of sites needed to cover the required area of planning can be obtained by dividing the total area by the area of site and take a real higher integer value which is so close to the result of the dividing.