The document discusses various radio propagation models used for modeling wireless channels. It describes that propagation models are important for determining coverage areas and improving channel quality. It divides models into outdoor and indoor applications. For outdoor models, it provides details of the Okumura and Hata models, including path loss calculations. It explains the Okumura model is based on measurements and widely used. The Hata model represents Okumura data graphically. For indoor models, it discusses factors like building materials and layouts that influence propagation. Models for partition losses, log-distance path loss, and attenuation factors are covered.

1. PROPAGATION
MODELS
Presented By
AYUSHI GAGNEJA
M.E Scholar
Electronics & Communication
Engineering
NITTTR-CHANDIGARH

2. Introduction to Radio
Wave Propagation
• The mobile radio channel places
fundamental limitations on the
performance of wireless communication
systems.
• Radio channels are extremely random
and do not offer easy analysis.

3. • Modeling radio channel is important
for:
–Determining the coverage area of a
transmitter
–Finding modulation and coding
schemes to improve the channel
quality

4. Radio Propagation Models
• Transmission path between sender and
receiver could be
–Line-of-Sight (LOS)
–Obstructed by buildings, mountains and
foliage
• Even speed of motion effects the
fading characteristics of the channel

5. BASIC DIVISION OF
PROPAGATION MODELS
• Different models have been developed to
meet the needs of realizing the propagation
behavior in different conditions.
• Types of models for radio propagation
include:
– Models for Outdoor Applications
– Models for Indoor Applications

6. Outdoor Propagation Model
• Radio transmission in mobile
communication takes place over irregular
terrain
• There are different propagation models
available to predict the signal strength,
Pr(d), by estimating the path loss at a
particular sector.

7. • Irregular terrain such as simple
curved earth profile, highly
mountainous or trees, building etc.
• Models used are based on systematic
interpretation of measurement data
obtained in the service area.
• They may vary in complexity and
accuracy.

8. - Longely Rice
- Durkins Model
- Okumura Model
- Hata Model
- Wideband PCS Microcell
- PCS Extension to Hata Model
- Walfisch – Bertoni Model
TYPES OF MODELS

9. Okumura Model
It is wholly based on measured data,
no analytical explanation
• among the simplest
• best in terms of path loss accuracy in
cluttered mobile environment
Okumura developed a set of curves in
urban areas with quasi-smooth terrain

10. • It is one of the most widely used
models for signal prediction in urban
areas.
• Applicable for the frequencies in the
range 150MHz to 1920MHz
• Distances of 1km to 100km
• Antenna heights from 30m to 1000m.

11. • Okumura developed a set of curves
giving the medium attenuation
relative to free space (Amu), with base
station effective antenna height (hte)
of 200m and a mobile antenna
height (hre) of 3m
• Curves are developed using vertical
omnidirectional antennas at both
base and mobile.

12. Estimating path loss
1. Determine free space loss, Amu(f,d),
between points of interest
2. Add Amu(f,d) and correction factors
to account for terrain

13. L50(dB)= LF + Amu(f,d) – G(hte) – G(hre) – GAREA
L50 = 50% value of propagation path loss
LF = free space propagation loss
Amu(f,d)= median attenuation relative to free space
G(hte) = base station antenna height gain factor
G(hre) = mobile antenna height gain factor
GAREA = gain due to environment

14. 70
60
50
40
30
20
10
Amu(f,d)(dB)
70 100 200 300 500 700 1000 2000
3000
f
(M
100
80
70
60
50
40
30
20
10
5
2
1
d(km)
Urban Area
ht = 200m
hr = 3m
Median Attenuation Relative to Free Space = Amu(f,d) (dB)
Amu(f,d) & GAREA
have been plotted
for wide range of
frequencies
Also G(hte)varies
at rate of
20dB/decade and
G(hre)varies at a
rate of
10dB/decade

15. G(hte) = 10m < hte < 1000m
G(hre) = hre ≤ 3m
G(hre) = 3m < hre <10m
model corrected for
• ∆h = terrain undulation height
• isolated ridge height
• average terrain slope
• mixed land/sea parameter

16. 16
35
30
25
20
15
10
5
0
GAREA(dB)
100 200 300 500 700 103
2⋅103
3 ⋅103
frequency (MHz)
suburban area
quasi open area
open area
Correction Factor = GAREA(dB)
When terrain
related
parameters
are calculated,
correction
parameters
are
added/subtrac
ted. These are
available as
Okumura
curves.

17. • Extrapolations of the derived curves can
be made to obtain values outside the
measurement range.
• Simplest and best in accuracy in path
loss prediction for cellular and land
mobile radio systems.

18. DISADVANTAGE:
•slow response to rapid terrain
changes, so not so good in rural areas.
•common standard deviations between
predicted & measured path loss ≈
10dB - 14dB

19. Hata Model
It is an empirical model of graphical path loss
data from Okumura
• Its range is valid from150 MHz to 1500
MHz
• Hata represented urban area propagation
loss as a standard formula and supplied for
correction equations for application to
some situations

20. • Okumura predicts median path loss
for different channels
• Propagation losses increase
• with frequency
• in built up areas

21. Parame
ter
Comment
L50 50th % value (median) propagation path
loss (urban)
fc frequency from 150MHz-1.5GHz
hte, hre Base Station and Mobile antenna height
α (hre) correction factor for hre , affected by
coverage area
d Tx-Rx separation
Standard formula for Median Path Loss

22. For small to medium sized city,
mobile antenna correction
factor is given by:
α (hre) = (1.1log10fc- 0.7)hre– (1.56log10fc- 0.8)
dB

23. For a large city, it is given as
α (hre) = 8.29(log101.54hre)2
– 1.1 dB
for (fc ≤ 300MHz)
α (hre) = 3.2(log1011.75hre)2
–
4.97 dB
for (fc > 300MHz)

24. To obtain path loss in a suburban
area, the standard Hata formula is
modified as:
L50 (dB) = L50 (urban) - 2[log10(fc/28)]2
– 5.4

25. For path loss in open rural areas,
the formula is modified as
L50(dB) = L50 (urban) - 4.78(log10 fc)2
-
18.33log10 fc - 40.98

26. PathLoss(dB)
hte (m)
160
155
150
145
140
135
130
125
120
20 60 100 140 180
20km
10km
5km
fc = 700MHz
PathLoss(dB)
Range (km)
0 4 8 12 16 20
180
170
160
150
140
130
120
110
100
900 MHz
700 MHz
• hte = 30m
• hre = 1m
Example Tables for Okumura-Hata Model
Terrain Legend
• Urban
• Suburban
• Open

27. HATA Model
• Mostly used in Radio frequency
• Predicting the behavior of cellular
communication in built up areas
• Applicable to transmission inside cities
• Suited for point to point and broadcast
communication.

28. INDOOR
PROPAGATION
MODEL

29. • With the advent of Personal
Communication Systems (PCS), we
need to characterize radio propagation
inside the buildings.
• Indoor radio channels are different
because
– The distances covered are much
smaller
– The variability of the environment is
much greater

30. • Smaller Tx-Rx separation distances than
outdoors
• Higher environmental variability for much
small Tx-Rx separation, conditions vary
from:
•Doors/windows open or not
•The mounting place of antenna: desk,
ceiling, etc.
•The level of floors

31. • Propagation inside the building is strongly influenced by
various features like
– layout of the building
– construction materials
– building type
– where the antenna mounted, …etc.
• Indoor radio propagation is dominated by 3 mechanisms
– Reflection
– Diffraction
– Scattering

32. • In general, indoor channels may be
classified either as Line of Sight, LOS or
Obstructed Sight, OBS with varying
degree of clutter
• The losses between floors of a building are
determined by the external dimensions and
materials of the building, as well as the
type of construction used to create the
floors and the external surroundings.

33. Building types
• Residential homes in suburban areas
• Residential homes in urban areas
• Traditional office buildings with fixed walls
(hard partitions)
• Open plan buildings with movable wall
panels (soft partitions)
• Factory buildings
• Grocery or Retail stores
• Sport arenas

34. Some Key Models
- Partition Losses – Same Floor
- Partition Losses – Different Floor
- Log-distance path loss model
- Ericsson Multiple Breakpoint Model
- Attenuation Factor Model

35. Partition Losses – Same Floor
• Buildings have a wide variety of
partitions and obstacles which form the
internal and external structure.
• There are mainly 2 types of partitions:
– hard partitions: immovable, part of building
– soft partitions: movable, lower than the
ceiling

36. • Partitions vary widely in their
physical and electrical properties.
• Path Loss depends upon the type of
partition

37. Average signal loss measurements for radio
paths obstructed by common building material

38. Partition Losses – Different Floor
Losses between floors of the building
are determined by
•External building dimensions
•Type of construction used to create the
floor
•External surroundings
•Number of windows
•Presence of tinting on windows

39. Total Floor Attenuation Factor and
Standard Deviation for 3 Buildings

40. Average Floor Attenuation Factor in dB
for 4 different floors in 2 office buildings

41. Indoor path loss obeys the distance power law
given by equation:
• n depends on surroundings and building type,
for free space it is 2
• Χσ = normal random variable in dB having
standard deviation σ dB
Log-distance Path Loss model

42. Path Loss Exponent for
Different Environments

43. Ericsson Multiple Breakpoint
Model
• It was obtained by measurements in a multiple
floor office building.
• It has 4 breakpoints and considers both an
upper and lower bound on path loss.
• It assumes that there is 30dB attenuation at d0 =
1m which is accurate for f = 900MHz & unity
gain antennas.

44. • Also it provides a deterministic
limit on range of path loss at given
distance
• It used a uniform distribution to
generate path loss values within
minimum &maximum range, as a
function of distance for in-building
simulation.

45. Path Loss Exponent and Standard
Deviation for different buildings

46. Ericsson’s in-building path loss
model

47. Attenuation Factor Model
• It includes effect of building type &
variations caused by obstacles.
• It provides flexibility and reduces
standard deviation between measured
and predicted path loss to 4dB
• Compared to standard deviation for path
loss with log-distance model i.e. 13dB
for 2 different buildings

48. nSF = exponent value for same floor measurement –
must be accurate
FAF = floor attenuation factor for different floor
PAF = partition attenuation factor for obstruction
encountered by primary ray tracing
Attenuation Factor Model is given by:

49. Primary Ray Tracing = single ray drawn between Tx & Rx
It yields good accuracy with good computational efficiency
FAF
PAF(1)
PAF(2)
Rx
Tx
σ decreases as average region becomes smaller-more
specific
Replace FAF with nMF =exponent for multiple floor loss

50. Path Loss Exponent and Standard
Deviation for different buildings
Standard
Deviation
decreases as
average region
becomes
smaller and
more site
specific.

51. Scatter plot illustrating actual measured
path loss in multi floored building 1

52. Scatter plot illustrating actual measured
path loss in multi floored building 2

53. In-Building Path Loss obeys free space +
loss factor (α)
• loss factor increases exponentially with d
∀α (dB/m) = attenuation constant for
channel
f α
850MHz 0.62
1.7GHz 0.57
4-story bldg
f α
850MHz 0.48
1.7GHz 0.35
2-story bldg

54. EXAMPLE
Calculate the mean path loss using Okumara’s
model for d=50km, hte=100m, hre=10m in a
suburban environment. If the base station
transmitter radiates an EIRP of 1kW at a
carrier frequency of 900 MHz, find
EIRP(dBm) and the power at the receiver
where gain at receiving antenna is 10dB.

56. G(hte) =
G(hre) =
= = -6 dB
= = 10.46 dB
Total mean path loss is
= 125.5 dB + 43 dB –(-6) dB – 10.46 dB -
9 dB
=155.4 dB
L50(dB)= LF + Amu(f,d) – G(hte) – G(hre) – GAREA

58. EXAMPLE
Find the mean path loss 30m from the
transmitter, through 3 floors of the Office
building 1. Assume 2 concrete block walls are
between the transmitter and receiver on the
intermediate floors. Mean path loss exponent
for same-floor measurements in a building is
n=3.27, mean path loss exponent for three-floor
measurements in a building is n=5.22, while
floor attenuation factor FAF=24.4 dB.

60. Mean path loss for same floor measurement is
= PL(1m) + 10*3.27*log(30) + 24.2 + 2*13
= 130.2 Db
Mean path loss for different floor measurement is
= PL(1m) + 10*5.22*log(30) + 2*13
= 108.6 dB

61. Thanks