This document summarizes a presentation on routing algorithms for low Earth orbit (LEO) satellite networks. It begins by defining the different types of satellite orbits - geostationary, medium Earth, highly elliptical, and low Earth orbit. It then focuses on LEO networks, discussing their architecture, applications, advantages over other networks, and open issues in routing. Several routing algorithms for LEO networks are also classified and described. The document concludes by stating that LEO networks are commonly used for broadcasting internet services due to their low cost and high data transmission rates.

1. Routing Algorithm for LEO
Satellite Networks : A Survey

2. A Presentation by:
Saif Shamim
Student - Department of Information science and Engineering
Acharya Institute of Technology
Bangalore – 560090, India
Email : saifshamim.ise.09@acharya.ac.in
Guided By:
Dr. Shiva Murthy G
Associate Professor
Department of Information science and Engineering
Acharya Institute of Technology
Bangalore – 560090, India
Email : shivamurthyg@acharya.ac.in

3. GEO
MEO
HEO
LEO

4. Types of Satellites
Geostationary/Geosync
hronous Earth Orbit
Satellites (GSOs)
(Propagation Delay:
250-280 ms)
Medium Earth Orbit
Satellites (MEOs)
(Propagation Delay:
110-130 ms)
Highly Elliptical
Satellites (HEOs)
(Propagation Delay:
Variable)
Low Earth Orbit
Satellite (LEOs)
(Propagation Delay: 20-
25 ms)

LEO: < 2K km
MEO: < 13K km (Odyssey, Inmarsat-P)
GEO: 33786 km
(Globalstar, Iridium, Teledesic)
This slide is taken from:
Ian F. Akyildiz
Satellite networks
Gerogia Institute of Technology, USA

5. Geosynchronous Orbit (GEO):
35,786 km above the earth
A geosynchronous
satellite is a satellite in
geosynchronous orbit,
with an orbital period the
same as the Earth's
rotation period.
There are approximately
300 operational
geosynchronous
satellites.
These can remain at one
position for infinite time.

6. Medium Earth Orbit (MEO): 8,000-
20,000 km above the earth
 Medium Earth orbit
(MEO), sometimes called
intermediate circular
orbit (ICO), is the region
of space around the Earth
above low Earth orbit and
below geostationary orbit.
 Telstar 1, an experimental
satellite launched in 1962.

7. Highly Elliptical Orbit Satellites
(HEOs)
From a few hundreds of km to 10s of
thousands allows to maximize the coverage of
specific Earth regions.
 Variable field of view and delay.
 Examples: MOLNIYA, ARCHIMEDES (Direct Audio
Broadcast), ELLIPSO.
This slide is taken from:
Ian F. Akyildiz
Satellite networks
Gerogia Institute of Technology, USA

8. Low Earth Orbit (LEO): 500-2,000
km above the earth
 A low Earth orbit (LEO) is
generally defined as an orbit below
an altitude of approximately 2,000
kilometers.
 A majority of artificial satellites
are placed in LEO.
Examples:
 Earth resource management
(Landsat, Spot, Radarsat)
 Paging (Orbcomm)
 Mobile (Iridium)
 Fixed broadband
(Teledesic, Celestri, Skybrid
ge)

9. Architecture of LEO
 Communications data passes through a
satellite using a signal path known as a
transponder.
 Typically satellites have between 24 and
72 transponders. A single transponder is
capable of handling up to 155 million bits
of information per second.
 With this immense capacity, today's
communication satellites are an ideal
medium for transmitting and receiving
almost any kind of content - from simple
voice or data to the most complex and
bandwidth-intensive video, audio and
Internet content.

10. Why LEO Satellite Networks?
 Less Propagation Delay
 High Throughput
 Flexible Bandwidth
 Digital Earth and Tele-Education
 Easy Integration
 Will Play an Important Role in Next Generation Networks (NGN)

11. Applications of Satellite Networks
 Telecommunication
 Earth Observation
 Military Operations
 Natural Calamities
 Broadcasting Internet

12. Routing Parameters
 Packet Loss Rate
 Delay Jitter
 Throughput
 Delay
 Average Node Throughput

13. Classification of Routing
Algorithms
 Steiner Tree Routing
 Destruction Resistance Routing
 Minimum Flow Maximum Residual
 BDSR Routing Algorithm
 A Handover Optimize Routing
Contd…

14.  Connection Oriented Routing
 Routing Based On Ground Station
 Optimization of Delay and Bandwidth
 High Performance Routing
 Distributed Multipath Routing
Classification of Routing
Algorithms

15. Classes of LEOs
 Little LEOs
–Non-voice services
–Orbcomm
–LEO One
–Final Analysis
Broadband LEOs
–High-speed data plus voice
–Teledesic
–SkyBridge
Big LEOs
–Voice plus limited data services
–Iridium
–Globalstar
–Constellation Communications This slide is taken from
Christhoper Reeding,
Overview of LEO Satellite Systems
National Communication & Information
Administration, USA

16. Open Issues
 Swarn Intelegence
 A Handover Problem
 TO satisfy all QoS Constraints
 To Reduce Onboard Complexity
 Combining GEO and LEO advantages

17. Conclusions
GEO Satellite Networks have advantage of technological
maturity and good coverage.
GEO Satellite Networks are suffering form high delay and
attenuation limits transmitting real time information.
Today LEO satellite networks are most commonly used in
broadcasting Internet. Due to low cost and high data
transmission rate these LEO satellite networks are the
preferred choice of the vendors.

18. Thank You

19. References
1. Satellite Networks, Ian F. Akyildiz Georgia Institute of
Technology, USA.
2. Overview of LEO Satellite Systems, Christhoper Reeding,
National Communication & Information Administration,
USA.
3. Dynamic Routing With Link State Information in ADNS and
future SATCOM Networks, Jun Sun, Mu-Cheng, Lorraine
Prior, Terrence Gibbons & Jeff Wysocarski, MIT Lincoln
Laboratory USA.