The High Altitude Long Operation (HALO) network is a broadband wireless Metropolitan Area Network (MAN) consisting of HALO aircraft operating at high altitude and carrying an airborne communications network hub, with network elements on the ground.. It will provide broadband services to businesses and to small offices home offices in an area containing a typical large city and its neighboring towns. To each end user, it will offer an unobstructed line of sight and a free-space like channel with short propagation delay, and it will allow the use of low power low-cost user terminals.

1. High Altitude Long Operation
Presented by
Mayuresh Bhagat

2. Contents
Introduction
HALO Network
System architecture
HALO Aircraft
Spectrum allocation
Reference model
User terminal
HALO Network services
Advantages
Disadvantage
Application
Reference

3. INTRODUCTION
 Demand for broadband wireless multimedia network
growing rapidly.
 HALO Network is a wireless MAN.
 High Altitude Aeronautical Platform Station (HAAPS) is
the technology used here.
 It combines the advantages of two well established
wireless communication networks,
 Terrestrial networks
 Satellite networks

4. SATELLITE COMMUNICATION NETWORK
Here the central node is satellite orbiting
around the earth in space. They have high look angles.
Disadvantages
• Expensive
• High power user terminals
• Long propagation delay
• Complex structure
• Cannot be maintained easily
• System capacity will be fixed

5. TERRESTRIAL COMMUNICATION NETWORK
It is simple wireless communication networks
used in cellular and personal communication systems. It
have low look angles.
Advantages
Less expensive
Low power user terminals
Short propagation delays
Scalability of capacity
Easy to maintain

6. HALO NETWORK
 Located at atmosphere above commercial airline traffic
and below satellite networks
 Wireless MAN in star topology
 HALO/proteous air plane is the central hub of the
network
 Provides many types of service
 HALO aero plane is specially designed for carry the
hub devices and they are having long lifetime.
 HAAPS is the basic idea behind HALO.

7. SYSTEM ARCHITECTURE

9. HALO/Proteus airplane
 It is a specially designed aircraft which can carry weight
of approximately 900 Kg.
The fuselage consists of ATM switches spot beam
antennas, multi beam antennas ,transmitters and receivers.
A fleet of 3 aircrafts are cycled in shifts to achieve
communication above an isolated city
Air plane maintains height in range 51,1000 to 60,000 ft.
The cone of commerce have diameter of 100 km at the
Minimum Look Angles(MLA) of 20 degree.
It can cover an area approximately 2000-3000 square miles

11. SPECTRUM ALLOCATION
 Variety of spectrum can be utilized by HALO
 # LMDS( Local Multimegabit Data Service at 28
GHz
 # Micro wave point to point at 38Ghz
 HALO utilizes multiple beam on ground arranged in
cellular pattern with each cell cover more than several
square miles of area.
 Dwell time: time duration for given beam spot at a
particular cell
 Ratcheting action provide beam to beam hand over and
communication when aircraft is orbiting

13. REFERENCE MODEL
With in HALO network 4 types of elements are connected,
Customer premises Equipment(low rate terminals)
Business premises Equipment(high rate terminals)
HALO Gate way( interfaces to non-HALO network)
Network control stations(control and maintenance)
3 types of signaling interfaces are there
UNI(User Network Interface)
B-ICI
NNI(Network Node Interface)

16. SUBSCRIBER UNITS
 It consist of three major sub group RF unit,
NIU(Network interface unit), and application terminals
such as PC, PSTN, video terminals
 The RF unit consists of tracking circuitry, MMW
transmitter and receiver.
 The NIU consists of high speed modulators
demodulators multiplexers and demultiplexers.
 The L band Frequency is used as IF for communication
 The connection between RU and NIU provided by
coaxial pair cables
 Minimal cost and easiness to maintain

18. HALO Network Services

19.  Schools hospital, small and large business… etc will get
benefit of HALO.
 Widely separated customers can receive same
communication as in entertainment broadcasting
 Mobile telephone services, paging one way broadcasting
and satellite concentrator.
 HALO PSTN interface provides services such as e-
commerce web browsing …etc
 LAN Ethernet bridging
 Service is based on “band width on demand”, providing
efficient use of available spectrum.
 Seamless large range multimedia services
 Can use in marine communication system.

20. ADVANTAGES
Capacity in range(10-100)Gb/sec
Low cost easy to maintain
Easy to implement
Low power unobstructed communication
Low propagation delay
Maximum use of bandwidth
Can be connected to non halo networks
It is stabilized
It uses broad band protocols ATM and SONET

21.  Presence of winds in the stratosphere.
 Not proven that planes can fly at stratospheric altitudes
for long stretches of time.
 Not proven that dirigibles can be stationed at
stratospheric altitude.
 Not proven that the position of weather balloons can be
controlled.
DISADVANTAGES

22.  Schools hospital, small, large, business… etc will get
benefit of HALO.
Widely separated customers can receive same
communication as in entertainment broadcasting.
We can access interactive TV and internet.
Can use as a LAN Ethernet bridging.
Can use in marine communication system.
APPLICATIONS

23. FUTURE SCOPE
 HAAPS technology will provide wireless broadbandHAAPS technology will provide wireless broadband
communication system.communication system.
 This technology will increase the capacity of satelliteThis technology will increase the capacity of satellite
network with minimum power to achieve good data rate.network with minimum power to achieve good data rate.
 The HALO aircraft can be flied on solar energy so thatThe HALO aircraft can be flied on solar energy so that
engine will get power from sun as well.engine will get power from sun as well.
 This centralized architecture will also result in improvedThis centralized architecture will also result in improved
efficiency of channel realization.efficiency of channel realization.
 In future experiments, HALO network will supportIn future experiments, HALO network will support
multimedia traffic that attempts to capture the effect ofmultimedia traffic that attempts to capture the effect of
integrated traffic typesintegrated traffic types

24. REFERENCES
1) G. Djuknic, J. Freidenfelds, et al., "Establishing Wireless Communications
Services via High-Altitude Aeronautical Platforms: A Concept Whose Time Has
Come?" IEEE Communications Magazine, September 1997.
2) J. Martin and N. Colella, "Broadband Wireless Services from High Altitude Long
Operation (HALO) Aircraft," SPIE Int'l. Symp. Voice, Video, and Data
Commun.: Broadband Eng. for Multimedia Markets, Dallas, TX, Nov. 1997.
3) N. Colella and J. Martin , "The Cone of Commerce," SPIE Int'l. Symp. Voice,
Video, and Data Commun.: Broadband Eng. for Multimedia Markets, Dallas, TX,
Nov. 1997.
4) F. Akyildiz, X. Wang, and N. Colella, "HALO (High Altitude Long Operation): a
Broadband Wireless Metropolitan Area Network," MOMUC '99, p.271–77, Nov.
1999.

25. Thank you