cell planning propagation model
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Walfish- Ikegami Model
ECE 486Prepared by: JCP
Walfish-Ikegami Model
The Walfish–Ikegami model is an empirical propagation model for an urban area, which is especially applicable for micro cells but can also be used for macro cells.
Walfish-Ikegami Model
Parameters in Walfish-Ikegami Model
W – street width (meters)φ- road orientation angle ( degrees)hroof – mean building heights, ave. over the calculation area (meters)b – mean value for building separation (center to center) metershms – height of mobile subscriber (meters)hBTS – height of BTS (meters)
Walfish-Ikegami ModelThe Walfish–Ikegami model separates into
two cases, which are the line-of-sight (LOS) and non-line- of-sight situations. The formula for path loss prediction in the LOS condition can be written as :
L = 42.6 + 26log d + 20log f
Where:
d – distance in km
f – frequency in Mhz
When no line-of-sight condition exists, the path loss
formula can be written as :
L = 32.4 + 20 log d + 20 log f + Lrts+L msd
Where:
Lrts is the rooftop–street diffraction and scatter loss
Lmsd is the multiscreen diffraction loss.
The path loss in the non-line-of-sight situation actually consists of three components:
rooftop–street diffraction and scatter loss,
multiscreen diffraction loss and
free space loss:
L0 = 32.4 + 20 log d + 20 log f
Walfish-Ikegami Model
The rule follows:
L = L0 + Lrts+Lmsd : Lrts + Lmsd > 0
L0 : Lrts + Lmsd ≤ 0
The rooftop–street diffraction and scatter loss is the loss occurring when the radio wave propagates from the closest rooftop to the receiver:
Lrts = −16.9 − 10 log w − 10 log f − 20 log(hroof − hRX) − L Ori
Walfish-Ikegami Model
where LOri is the street orientation loss
Walfish-Ikegami ModelThe multiscreen diffraction loss is caused by
propagation from the BTS to the rooftop, which is closest to the MS:
Walfish-Ikegami ModelWhere:
Walfish-Ikegami ModelThe parameter ka increases the path loss in case the
BTS is below the rooftop.
The parameters kd and kf are for adjusting the correlation between the distance and frequency with multiscreen diffraction.
The Walfish–Ikegami model is valid for the frequency range 800–200 MHz.
The range for the base station antenna height is from 4 to 50 meters, mobile antenna height from 1 to 3 meters and distance between the transmitter and receiver from 20 to 5000 meters.
