Satellite ATM

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(No Transcript)
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Why Satellite ATM Networks?

• Wide geographical area coverage
• From kbps to Gbps communication everywhere
• Faster deployment than terrestrial
  infrastructures
• Bypass clogged terrestrial networks and are
  oblivious to terrestrial disasters
• Supporting both symmetrical and asymmetrical
  architectures
• Seamless integration capability with terrestrial
  networks
• Very flexible bandwidth-on-demand capabilities
• Flexible in terms of network configuration and
  capacity allocation
• Broadcast, Point-to-Point and Multicast
  capabilities
• Scalable

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Orbits

• Defining the altitude where the satellite will
  operate.
• Determining the right orbit depends on proposed
  service characteristics such as coverage,
  applications, delay.

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Orbits (cont.)
GEO (33786 km)
GEO Geosynchronous Earth Orbit MEO Medium Earth
Orbit LEO Low Earth Orbit
Outer Van Allen Belt (13000-20000 km)
MEO ( lt 13K km)
?
LEO ( lt 2K km)
Inner Van Allen Belt (1500-5000 km)
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Types of Satellites

• Geostationary/Geosynchronous 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)

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Geostationary/Geosynchronous Earth Orbit
Satellites (GSOs)

• 33786 km equatorial orbit
• Rotation speed equals Earth rotation speed
  (Satellite seems fixed in the horizon)
• Wide coverage area
• Applications (Broadcast/Fixed Satellites, Direct
  Broadcast, Mobile Services)

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Advantages of GSOs

• Wide coverage
• High quality and Wideband communications
• Economic Efficiency
• Tracking process is easier because of its
  synchronization to Earth

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Disadvantages of GSOs

• Long propagation delays (250-280 ms).(e.g.,
  Typical Intern. Tel. Call ? 540 ms round-trip
  delay. Echo cancelers needed. Expensive!)(e.g.,
  Delay may cause errors in data Error correction
  /detection techniques are needed.)
• Large propagation loss. Requirement for high
  power level.(e.g., Future hand-held mobile
  terminals have limited power supply.)Currently
  smallest terminal for a GSO is as large as an A4
  paper and as heavy as 2.5 Kg.

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Disadvantages of GSOs (cont.)

• Lack of coverage at Northern and Southern
  latitudes.
• High cost of launching a satellite.
• Enough spacing between the satellites to avoid
  collisions.
• Existence of hundreds of GSOs belonging to
  different countries.
• Available frequency spectrum assigned to GSOs is
  limited.

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Medium Earth Orbit Satellites (MEOs)

• Positioned in 10-13K km range.
• Delay is 110-130 ms.
• Will orbit the Earth at less than 1 km/s.
• Applications
• Mobile Services/Voice (Intermediate Circular
  Orbit (ICO) Project)
• Fixed Multimedia (Expressway)

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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.

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Low Earth Orbit Satellites (LEOs)

• Usually less than 2000 km (780-1400 km are
  favored).
• Few ms of delay (20-25 ms).
• They must move quickly to avoid falling into
  Earth ? LEOs circle Earth in 100 minutes at 24K
  km/hour. (5-10 km per second).
• Examples
• Earth resource management (Landsat, Spot,
  Radarsat)
• Paging (Orbcomm)
• Mobile (Iridium)
• Fixed broadband (Teledesic, Celestri, Skybridge)

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Low Earth Orbit Satellites (LEOs) (cont.)

• Little LEOs 800 MHz range
• Big LEOs gt 2 GHz
• Mega LEOs 20-30 GHz

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Comparison of Different Satellite Systems
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Comparison of Satellite Systems According to
their Altitudes (cont.)
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Why Hybrids?

• GSO LEO
• GSO for broadcast and management information
• LEO for real-time, interactive
• LEO or GSO Terrestrial Infrastructure
• Take advantage of the ground infrastructure

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Frequency Bands

• NarrowBand Systems
• L-Band ? 1.535-1.56 GHz DL
  1.635-1.66 GHz UL
• S-Band ? 2.5-2.54 GHz DL
  2.65-2.69 GHz UL
• C-Band ? 3.7-4.2 GHz DL 5.9-6.4
  GHz UL
• X-Band ? 7.25-7.75 GHz DL 7.9-8.4
  GHz UL

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Frequency Bands (cont.)

• WideBand/Broadband Systems
• Ku-Band ? 10-13 GHz DL 14-17
  GHz UL(36 MHz of channel bandwidth enough for
  typical 50-60 Mbps applications)
• Ka-Band ? 18-20 GHz DL 27-31
  GHz UL(500 MHz of channel bandwidth enough for
  Gigabit applications)

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Next Generation Systems Mostly Ka-band

• Ka band usage driven by
• Higher bit rates - 2Mbps to 155 Mbps
• Lack of existing slots in the Ku band
• Features
• Spot beams and smaller terminals
• Switching capabilities on certain systems
• Bandwidth-on-demand
• Drawbacks
• Higher fading
• Manufacturing and availability of Ka band devices
• Little heritage from existing systems (except
  ACTS and Italsat)

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Frequency Bands (cont.)

• New Open Bands (not licensed yet)
• GHz of bandwidth
• Q-Band ? in the 40 GHz
• V-Band ? 60 GHz DL 50 GHz UL

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Space Environment Issues

• Harsh ? hard on materials and electronics (faster
  aging)
• Radiation is high (Solar flares and other solar
  events Van Allen Belts)
• Reduction of lifes of space systems (12-15 years
  maximum).

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Space Environment Issues (cont.)

• Debris (specially for LEO systems) (At 7 Km/s
  impact damage can be important. Debris is going
  to be regulated).
• Atomic oxygen can be a threat to materials and
  electronics at LEO orbits.
• Gravitation pulls the satellite towards earth.
• Limited propulsion to maintain orbit (Limits the
  life of satellites Drags an issue for LEOs).
• Thermal Environment again limits material and
  electronics life.

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Basic Architecture
SIU - Satellite Interworking Unit
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ATM-Satellite Configuration
Satellite
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3.2. ATM Satellite Interworking Unit (ASIU)
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Payload Concepts

• Bent Pipe Processing
• Onboard Processing
• Onboard Switching

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Bent Pipe Processing

• Amplifies (repeats) the received signals
• Does not require demodulation/modulation of
  signals
• Simple payload (but little flexibility)

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Bent-Pipe Protocol Stack (IP over ATM)
Satellite
Physical
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3.5 Onboard Processing (Transparent)

• Regenerates the received frequencies (3 dB gain)
• Requires demodulation/modulation of signals
• Digital payload (can be multibeam)
• Used mostly for mobile systems

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Onboard Processing Protocol Stack (IP over ATM)
Satellite
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Onboard Switching

• Regenerates the received frequencies (3 dB gain)
• Digital baseband switching multibeam payload
• Baseline for most future satellite systems

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Onboard Switching Protocol Stack (IP over ATM)
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LAN/MAN Interconnection
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LAN/MAN Internetworking Protocol Architecture
USER
USER
Applications Higher Layers
Applicat-ions Higher Layers
Communication Satellite
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TCP/ UDP
TCP/UDP
IP
IP
3
LMAPC
LMAPC
2b
LLC
LLC
LLC
LLC
LLC
LLC
MAC. (IEEE 802 3,5,6
MAC (IEEE 802.3,5,6
AAL
MAC (IEEE 802.3,5,6
MAC (IEEE 802.3,5,6
AAL
2a
ATM
ATM
Satellite Modem I/F
Satellite Modem I/F
Physical
Physical
Physical
Physical
Physical
Physical
1
Satellite Modem
Satellite Modem
ASIU
ASIU
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A NEW PROTOCOL SUITE FOR SATELLITE NETWORKS
RCS
IPv4/IPv6
AAL5
AAL2x
ATM
AFEC
MAC (WISPER-2)
Physical
IP-ATM-Satellite Configuration
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TCP Problems in Satellite Networks

• Long Propagation Delays
• - Long duration of the Slow Start phase -gt TCP
  sender does not use the available bandwidth
• - cwnd lt rwnd.
• The transmission rate of the sender is bounded.
  The higher RTT the lower is the bound on the
  transmission rate for the sender.

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TCP Problems in Satellite Networks

• High link error rates
• - The TCP protocol was initially designed to
  work in networks with low link error rates, i.e.,
  all segment losses were mostly due to network
  congestion. As a result the TCP sender decreases
  its transmission rate -gt causes unnecessary
  throughput degradation if segment losses occur
  due to link errors

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TCP Problems in Satellite Networks

• Asymmetric Bandwidth
• - ACK packets may congest the reverse channel,
  and be delayed or lost -gt Traffic burstiness
  increases and Throughput decreases

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Duration of the Slow Start for LEO, MEO and GEO
Satellites
Satellite Type RTTmsec TSlowStart (B1Mb/sec) TSlowStart (B10Mb/sec) TSlowStart (B155Mb/sec)
LEO 50 0.18 sec 0.35 sec 0.55 sec
MEO 250 1.49 sec 2.32 sec 3.31 sec
GEO 550 3.91 sec 5.73 sec 7.91 sec
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TCP Peach A New Congestion Scheme for Satellite
Networks

• Sudden Start ()
• Congestion Avoidance
• Fast Retransmit
• Rapid Recovery ()

• I. F. Akyildiz, G. Morabito, S. Palazzo,TCP
  Peach A New Flow Control Scheme for Satellite
  Networks. IEEE/ACM Transactions on Networking,
  June 2001.

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TCP-Peach Scheme
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Comparison Between the Sudden Start and the Slow
Start
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What is Handover?

• Leo Satellites circulate the Earth at a constant
  speed.
• Coverage area of a LEO satellite changes
  continuously.
• Handover is necessary between end-satellites.

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Types of Handover
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Footprint and Orbit Periods
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Handover Management Through Re-routingUzunalioglu
, H., Akyildiz, I.F., Yesha, Y., and Yen W.,
"Footprint Handover Rerouting Protocol for LEO
Satellite Networks," ACM-Baltzer Journal of
Wireless Networks (WINET), Vol. 5, No. 5, pp.
327-337, November 1999. 
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Footprint Re-routing (FR)
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Routing Algorithms for Satellite Networks

• Satellites organized in planes
• User Data Links (UDL)
• Inter-Satellite Links (ISL)
• Short roundtrip delays
• Very dynamic yet predictable network topology
• Satellite positions
• Link availability
• Changing visibility from the Earth

http//www.teledesic.com/tech/mGall.htm
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LEOs at Polar Orbits

• Seam
• Border between counter-rotating satellite planes
• Polar Regions
• Regions where the inter-plane ISLs are turned off

• E. Ekici, I. F. Akyildiz, M. Bender, The
  Datagram Routing Algorithm for Satellite IP
  Networks ,
• IEEE/ACM Transactions on Networking, April 2001.
  
• E. Ekici, I. F. Akyildiz, M. Bender, A New
  Multicast Routing Algorithm for Satellite IP
  Networks,
• IEEE/ACM Transactions on Networking, April 2002.

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IP-Based Routing in LEO Satellite Networks

• Datagram Routing
• Darting Algorithm
• Geographic-Based
• Multicast Routing
• No scheme available

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Routing in Multi-Layered Satellite Networks
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Multi-Layered Satellite RoutingI.F. Akyildiz, E.
Ekici and M.D. Bender, MLSR A Novel Routing
Algorithm for Multi-Layered Satellite IP
Networks, IEEE/ACM Transactions on Networking,
June 2002.

• Satellite Architecture
• Consists of multiple layers (here 3)
• UDL/ISL/IOL
• Terrestrial gateways connected to at least one
  satellite

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Iridium Network
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Iridium Network (cont.)
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Iridium Network (cont.)

• 6 orbits
• 11 satellites/orbit
• 48 spotbeams/satellite
• Spotbeam diameter 700 km
• Footprint diameter 4021km
• 59 beams to cover United States
• Satellite speed 26,000 km/h 7 km/s
• Satellite visibility 9 - 10 min
• Spotbeam visibility lt 1 minute
• System period 100 minutes

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Iridium Network (cont.)

• 4.8 kbps voice, 2.4 Kbps data
• TDMA
• 80 channels /beam
• 3168 beams globally (2150 active beams)
• Dual mode user handset
• User-Satellite Link L-Band
• Gateway-Satellite Link Ka-Band
• Inter-Satellite Link Ka-Band

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Operational Systems
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Operational Systems (cont.) Little LEOs
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Proposed and Operational Systems

• ICO Global Communications (New ICO)
• Number of Satellites 10
• Planes 2
• Satellites/Plane 5
• Altitude 10,350 km
• Orbital Inclination 45
• Remarks
• Service Voice _at_ 4.8 kbps, data _at_ 2.4 kbps and
  higher
• Operation anticipated in 2003
• System taken over by private investors due to
  financial difficulties
• Estimated cost 4,000,000,000
• 163 spot beams/satellite, 950,000 km2 coverage
  area/beam, 28 channels/beam
• Service link 1.98-2.01 GHz (downlink), 2.17-2.2
  GHz (uplink) (TDMA)
• Feeder link 3.6 GHz band (downlink), 6.5 GHz
  band (uplink)

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Proposed and Operational Systems (cont.)

• Globalstar
• Number of Satellites 48
• Planes 8
• Satellites/Plane 6
• Altitude 1,414 km
• Orbital Inclination 52
• Remarks
• Service Voice _at_ 4.8 kbps, data _at_ 7.2 kbps
• Operation started in 1999
• Early financial difficulties
• Estimated cost 2,600,000,000
• 16 spot beams/satellite, 2,900,000 km2 coverage
  area/beam,175 channels/beam
• Service link 1.61-1.63 GHz (downlink), 2.48-2.5
  GHz (uplink) (CDMA)
• Feeder link 6.7-7.08 GHz (downlink), 5.09-5.25
  GHz (uplink)

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Proposed and Operational Systems (cont.)

• ORBCOM
• Number of Satellites 36
• Planes 4 2
• Satellites/Plane 2 2
• Altitude 775 km 775 km
• Orbital Inclination 45 70
• Remarks
• Near real-time service
• Operation started in 1998 (first in market)
• Cost 350,000,000
• Service link 137-138 MHz (downlink), 148-149 MHz
  (uplink)
• Spacecraft mass 40 kg

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Proposed and Operational Systems (cont.)

• Starsys
• Number of Satellites 24
• Planes 6
• Satellites/Plane 4
• Altitude 1,000 km
• Orbital Inclination 53
• Remarks
• Service Messaging and positioning
• Global coverage
• Service link 137-138 MHz (downlink), 148-149 MHz
  (uplink)
• Spacecraft mass 150 kg

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Proposed and Operational Systems (cont.)

• Teledesic (original proposal)
• Number of Satellites 840 (original)
• Planes 21
• Satellites/Plane 40
• Altitude 700 km
• Orbital Inclination 98.2
• Remarks
• Service FSS, provision for mobile service
  (16 kbps 2.048 Mbps, including video) for
  2,000,000 users
• Sun-synchronous orbit, earth-fixed cells
• System cost 9,000,000,000 (2000 for terminals)
• Service link 18.8-19.3 GHz (downlink), 28.6-29.1
  GHz (uplink) (Ka band)
• ISL 60 GHz
• Spacecraft mass 795 kg

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Proposed and Operational Systems (cont.)

• Teledesic (final proposal)
• Number of Satellites 288 (scaled down)
• Planes 12
• Satellites/Plane 24
• Altitude 700 km
• Remarks
• Service FSS, provision for mobile service
  (16 kbps 2.048 Mbps, including video) for
  2,000,000 users
• Sun-synchronous orbit, earth-fixed cells
• System cost 9,000,000,000 (2000 for terminals)
• Service link 18.8-19.3 GHz (downlink), 28.6-29.1
  GHz (uplink) (Ka band)
• ISL 60 GHz
• Spacecraft mass 795 kg

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HALOTM Network A Wireless Broadband
Metropolitan Area Network
Frequency Options - 28 or 38 GHz Service
Availability
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HALOTM Network (cont.)
HALO Network Hub
Business Premise Equipment
67
HALOTM Network (cont.) Mobility Model
68
A StratosphericCommunications Layer
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Interconnection of HALOTM Networks
70
References Published in BWN Lab(http//www.ece.ga
tech.edu/research/labs/bwn/)

• Survey Paper
• Akyildiz, I.F. and Jeong, S., "Satellite ATM
  Networks A Survey," IEEE Communications
  Magazine, Vol. 35, No. 7, pp.30-44, July 1997.

71
References Published in BWN Lab(http//www.ece.ga
tech.edu/research/labs/bwn/)

• 2. Transport Layer
• Akyildiz, I.F., Morabito, G., and Palazzo, S.,
  "TCP Peach for Satellite Networks Analytical
  Model and Performance Evaluation,'' International
  Journal of Satellite Communications, Vol. 19, pp.
  429-442, October 2001.
• Akyildiz, I.F., Morabito, G., Palazzo, S., "TCP
  Peach A New Congestion Control Scheme for
  Satellite IP Networks,'' IEEE/ACM Transactions on
  Networking, Vol. 9, No. 3, June 2001.  
• Akyildiz, I.F., Morabito, G., Palazzo, S.,
  Research Issues for Transport Protocols in
  Satellite IP Networks,'' IEEE PCS (Personal
  Communications Systems) Magazine, Vol. 8, No. 3,
  pp. 44-48, June 2001.
• Morabito, G., Tang, J., Akyildiz, I.F., and
  Johnson, M., A New Rate Control Scheme for
  Real-Time Traffic in Satellite IP Networks,''
  IEEE Infocom'01, April 2001, Alaska.

72
References Published in BWN Lab(http//www.ece.ga
tech.edu/research/labs/bwn/)

• 2. Transport Layer (cont.)
• Morabito, G., Akyildiz, I.F., Palazzo S., "Design
  and Modeling of a New Flow Control Scheme (TCP
  Peach) for Satellite Networks" IFIP-TC6/ European
  Union Networking 2000 Conference Broadband
  Satellite Workshop, Paris, France, May 2000. 
• Morabito G., Akyildiz, I.F., Palazzo, S., "ABR
  Traffic Control for Satellite ATM Networks," IEEE
  Globecom'99 Conference, Rio De Janeiro, December
  1999.
• Handover Management
• Cho, S., Akyildiz I. F., Bender M. D., and
  Uzunalioglu H., "A New Connection Admission
  Control for Spotbeam Handover in LEO Satellite
  Networks," to appear in ACM-Kluwer Wireless
  Networks Journal, 2002.
• Cho, S.R., Akyildiz, I.F., Bender, M.D., and
  Uzunalioglu, H., A New Spotbeam Handover
  Management Technique for LEO Satellite
  Networks,'' Proc. of IEEE GLOBECOM 2000, San
  Francisco, CA, November 2000. 

73
References Published in BWN Lab(http//www.ece.ga
tech.edu/research/labs/bwn/)

• 3. Handover Management (cont.)
• Cho, S., Adaptive Dynamic Channel Allocation
  Scheme for Spotbeam Handover in LEO Satellite
  Networks,'' to appear in the IEEE Vehicular
  Technology Conference (IEEE VTC) 2000, Boston,
  MA, September, 2000.
• McNair, J., Location Registration in Mobile
  Satellite Systems'', Proc. of the 5th IEEE
  Symposium on Computers and Communications (ISCC
  2000), July 2000. 
• Akyildiz, I.F., Uzunalioglu, H., and Bender,
  M.D., "Handover Management in Low Earth Orbit
  (LEO) Satellite Networks," ACM-Baltzer Journal of
  Mobile Networks and Applications (MONET), Vol. 4,
  No. 4, pp. 301-310, December 1999. 
• Uzunalioglu, H., Akyildiz, I.F., Yesha, Y., and
  Yen W., "Footprint Handover Rerouting Protocol
  for LEO Satellite Networks," ACM-Baltzer Journal
  of Wireless Networks (WINET), Vol. 5, No. 5, pp.
  327-337, November 1999. 

74
References Published in BWN Lab(http//www.ece.ga
tech.edu/research/labs/bwn/)

• 3. Handover Management (cont.)
• Uzunalioglu, H., Evans, J.W., and Gowens, J., A
  Connection Admission Control Algorithm for Low
  Earth Orbit (LEO) Satellite Networks,'' Proc. of
  IEEE ICC'99, pp. 1074 - 1078, Vancouver, Canada,
  June 1999.
• Uzunalioglu, H., and Yen W., Managing Connection
  Handover in Satellite Networks,'' Proc. IEEE
  GLOBECOM '97, pp. 1606-1610, Phoenix, Arizona,
  Dec. 1997. 
• Uzunalioglu, H., Yen W., and Akyildiz, I.F.,
  "Handover Management in LEO Satellite ATM
  Networks," Proc. of the ACM/IEEE MobiCom'97, pp.
  204-214, October 1997.

75
References Published in BWN Lab(http//www.ece.ga
tech.edu/research/labs/bwn/)

• 4. Routing
• Akyildiz, I.F., Ekici, E., and Bender, M.D.,
  "MLSR A Novel Routing Algorithm for
  Multi-Layered Satellite IP Networks", April 2001
  Revised in September 2001.  
• Ekici, E., Akyildiz, I.F., and Bender, M., A
  Multicast Routing Algorithm for LEO Satellite IP
  Networks,'' to appear in IEEE/ACM Transactions on
  Networking, April 2002.  
• Ekici, E., Akyildiz, I.F., Bender, M., "A
  Distributed Routing Algorithm for Datagram
  Traffic in LEO Satellite Networks," IEEE/ACM
  Transactions on Networking, Vol. 9, No. 2, pp.
  137-148, April 2001.  
• Ekici, E., Akyildiz, I.F., and Bender, M.D.,
  "Network Layer Integration of Terrestrial and
  Satellite IP Networks over BGP-S" Proceedings of
  GLOBECOM 2001, San Antonio, TX, Nov. 25-29, 2001.
• Uzunalioglu, H., Akyildiz, I.F., and Bender,
  M.D., A Routing Algorithm for LEO Satellite
  Networks with Dynamic Connectivity,'' ACM-Baltzer
  Journal of Wireless Networks (WINET), Vol. 6, No.
  3, pp. 181-190, June 2000.

76
References Published in BWN Lab(http//www.ece.ga
tech.edu/research/labs/bwn/)

• 4. Routing (cont.)
• Ekici, E., Akyildiz, I.F., Bender, M.D.,
  "Datagram Routing Algorithm for LEO Satellite
  Networks'' IEEE INFOCOM'2000, Israel, March 2000.
• Uzunalioglu, H., Probabilistic Routing Protocol
  for Low Earth Orbit Satellite Networks,'' Proc.
  of the IEEE ICC'98, Atlanta, pp. 89-93, June
  1998.
• HALO Network
• Colella, N.J., Martin, J., and Akyildiz, I.F.,
  "The HALO Network,'' IEEE Communications
  Magazine, Vol. 38, No. 6, pp. 142-148, June 2000.
• Akyildiz, I.F., Wang, X., and Colella, N., "HALO
  (High Altitude Long Operation) A Broadband
  Wireless Metropolitan Area Network,'' IEEE
  MoMuC'99 (Mobile Multimedia Communication
  Conference), San Diego, November 1999.