1. Ben-Gurion University of the Negev Department of communication systems engineering
Effects of build-up terrain on radio signal fading in land-satellite communication links
Supervisor: Prof. Natan Blaunstein
Student: Ilya Liberman

2. Satellite Communication

3. Satellite applications
Global positioning system (GPS)
• Communications with ships at sea
-Morse service ended last year for commercial vessels
• Communications with land base stations
Direct broadcast TV

4. Sattelite links

5. Mobile Radio Propagation
Radio signals propagate according to three
mechanisms
– reflection
– diffraction
– scattering

6. Mobile Radio Propagation
Result of the three mechanisms are three nearly independent phenomena:
Path loss fading
-Reduction in power density of an electromagnetic wave as it
propogates throught space
Fast fading (multipath fading)
-Phenomenon that results in radio signals reaching the receiving
antenna by two or more paths
Slow Fading (Shadowing fading)
-Occurs when a mobile moves behind an obstruction

7. Saunder’s physical statistical model
Makes use of statistical distribution of physical parameters
A mobile situated on a long straight street with direct ray from the satellite impinging on the mobile from arbitrary direction
Street is lined on both sides with buildings whose height varies randomly
No line of sight between sattelite and base station

8. Rayleigh build up distribution
Rayleight comulative distribution function
=Building height
=Standard deviation of buildings height

9. General problem

10. Multi-parametric stochastic model
Covers both LOS and NLOS states
CDF=F(z,n)=
CDF=Cumulative distribution function.Determines the probability of an event for wich z<h
h1=minimum height of built-up layer
h2=maximum height of built-up layer
H(x)=Heaviside unit step function
z=Building height
n=terrain parameter

11. CDF as a function of building height and n parameter
n high=> more low build-up terrain then high
n small=> more high build-up terrain then low
n=1=>building height uniformly distributed in the range h1 to h2

12. SIMULATIONS Simulation written in mathematica-tool
Simulation performed for cities of Westminster and Guildford
Westminster Guildford

13. Westminster city-simulation results Maximum building height: 90(m) Parameters: Minimum building height: close to zero Standard deviation :

14. Guildford city-simulation results Maximum building height: 20(m) Minimum building height: close to zero Standard deviation :

15. Conclusions Saunder’s physical statistical model gives
precise results for high terrain only
Multi-parametric stochastic model gives precise results for both low and high terrain

16. Thank you