1. Practical Radio Propagation Models

2. Radio Propagation Models

3. Radio propagation model equations
Log-distance path model
Average received power
Average path loss
Log-normal shadowing model

4. Outdoor Propagation Models
Okumura’s Model
Most widely used models for signal prediction in urban areas
Applicable in frequency range of 150 MHz-1920 MHz and distances of 1 km – 100 km
Base station heights of 30 m – 1000 m

5. Okumura Model equations
- Median value of propagation path loss
- Free space propagation loss
- Median attenuation relative to free-space
- Base station antenna height gain factor
- Mobile antenna height gain factor
- Gain due to type of environment

6. Free space propagation loss LF
LF = -10 log [ l2/ (4pd)2]
Wavelength l,m = 3 x 108/f
Frequency f, Hz
d = Transmitter-receiver distance, m

7. Gain factor calculations

8. Median attenuation relative to free space (Amu(f,d)), over a quasi-smooth terrain [ from Oku68 © IEEE]
100 70
Urban Area
ht = 200m
hr = 3m 80 70 60 60 50 50 40
d (km) 30
Median Attenuation, A(f,d) (dB) 40 20 10 5 30 2 1 20 10 70
100
200
300
500
1000
2000
700
3000
Frequency f (MHz)

9. Correction factor, GAREA, for different types of terrain [ from Oku68 ©IEEE]35 30
Open Area 25 20
Quasi Open Area 15
Correction Factor , GAREA (dB)
Suburban Area 10 5
100
200
300
500
1000
2000
700
3000
Frequency f (MHz)

10. Hata Model for different terrains|

11. Hata Model parameters - Frequency in MHz from 150 MHz - 1500 MHz
- Effective transmitter ( base station) antenna height (in meters) ( 30 m – 200 m)
- Effective receiver ( mobile) antenna height (in meters) ( 1 m – 10 m)
- T-R separation distance in km
- Correction factor for effective for effective mobile height

12. Correction factor
Small City
Large City

13. PCS Extension to Hata Model
Extension of Hata Model to GHz
Developed by EURO-COST ( European Cooperative for Scientific & Tech. Research)

14. PCS Extension to Hata Model limits
Model valid for following range of parameters

15. Indoor Propagation Models
PCS (Personal Communication System) requires good models for propagation inside buildings
Indoor radio channel differs from outdoor models
Distances covered are much smaller
Variability of channel is much greater for a much smaller T-R separation distance
Indoor channels may be classified as either Line-of-sight (LOS) or Obstructed (OBS)

16. Log-distance indoor model
Log-normal power law
where n, s depend on surrounding & building type

17. Log-distance indoor model- Example
Given the following measurements:
Pr (1 m) = 0 dBm
Pr (2 m) = -20 dBm
Pr (5 m) = -30 dBm
Pr (10 m) = -40 dBm
Determine the value of n and s using log-distance model

18. Log-distance indoor model- Solution
Step 1: Predicted vlaues
Using Pr’(d) = Pr(d0) – 10nlog(d/d0)
Pr’(1) = 0 dBm – 10nlog(1/1) = 0
Pr’ (2 m) = 0 dBm – 10nlog(2/1)=-3n
Pr (5 m) = 0 dBm – 10nlog(5/1)=-7n
Pr (10 m)=0 dBm–10nlog(10/1)=-10n

19. Log-distance indoor model- Solution
Step 2: Mean squared error E between measured and predicted values
E= (0-0)2 + (-20+3n)2+(-30+7n)2+(-40+10n)2
Step 3: Minimization of error E
dE/dn = 0
=> 2 x 3 x (-20+3n) +2 x 7 x (-30+7n) +2 x 10 x ( n) = 0 
=> 158n = 670 => n = 4.24

20. Log-distance indoor model- Solution
Step 4: Calculation of standard deviation s
s2 = E/Number of measurements
=[(0-0)2 + (-20+3n)2+(-30+7n)2+(-40+10n)2]/4
Putting n = 4.24
s2 = 14.72
=> s = 3.83

21. Path Loss Exponent and Standard Deviation Measured in Commericial/Office Buildings [Anderson et al., 94]
Building
Frequency (MHz) n
(db)
Retail Stores
914
2.2
8.7
Grocery Store
1.8
5.2
Office, hard partition
1500
3.0
7.0
Office, soft partition
900
2.4
9.6
1900
2.6
14.1 s †

22. Path Loss Exponent and Standard Deviation Measured in Factory (LOS) Buildings [Anderson et al., 94]
Frequency (MHz) n
(db)
Factory LOS
Textile/Chemical
1300
2.0
3.0
4000
2.1
7.0
Paper/Cereals
1.8
6.0
Metalworking
1.6
5.8 s †

23. Path Loss Exponent and Standard Deviation Measured in Home/Factory (OBS)Buildings [Anderson et al. 94]
Building
Frequency (MHz) n
(db)
Suburban Home
Indoor to Street
900
3.0
7.0
Factory OBS
Textile/Chemical
4000
2.1
9.7
Metalworking
1300
3.3
6.8 s †

24. Seidel Model – Same floor measurements
In-building site-specific propagation model
Reduces the standard deviation (s) between measured and predicted path loss to around 4dB, as compared to 13dB when only a log-distance model was used
nSF = ‘same floor’ measurement exponent
FAF = Floor attenuation factor for a specified number of building floors
PAF = Partition attenuation factor

25. Seidel Model – Multi floor measurements
When measurments are made across different floors, then model is modified:
nMF = ‘multifloor’ measurement exponent
PAF = Partition attenuation factor

26. Path Loss Exponent and Standard Deviation Measured for All Buildings [Seidel et al., 1992]
s (db)
Number of locations
All Buildings
All locations
3.14
16.3
634
Same Floor
2.76
12.9
501
Through One Floor
4.19
5.1 73
Through Two Floors
5.04
6.5 30
Through Three Floors
5.22
6.7
Grocery Store
1.81
5.2 89
Retail Store
2.18
8.7
137

27. Path Loss Exponent and Standard Deviation Measured for Office Building 1 [Seidel et al., 1992]
s (db)
Number of locations
Office Building 1:
Entire Building
3.54
12.8
320
Same Floor
3.27
11.2
2.38
West Wing 5th Floor
2.68
8.1
104
Central Wing 5th Floor
4.01
4.3
118
West Wing 4th Floor
3.18
4.4
120

28. Path Loss Exponent and Standard Deviation Measured for Office Building 2 [Seidel et al., 1992]
s (db)
Number of locations
Office Building 2:
Entire Building
4.33
13.3
100
Same Floor
3.25
5.2 37

29. Free-space plus linear Path Attenuation Model [Devasirvathan et al, 90]
- Attenuation constant for channel (dB/n)
FAF- Floor attentuation factor
PAF- Partition attentuation factor

30. Free Space Plus Linear Path Attenuation Model parameters [Devasirvathan et al, 90]
Location
Frequency
a —Attenuation (dB/m)
Building 1:4 story
850 MHz
0.62
1.7 GHz
0.57
4.0 GHz
0.47
Building 2:2 story
0.48
0.35
0.23 †