1. High Altitude Long Operation

2. Contents Introduction HALO Network System architecture HALO Aircraft
Spectrum allocation
Reference model
User terminal
HALO Network services
Advantages
Conclusion
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 COMMINICATION 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 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 circuitary,MMW transmiter 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,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 satelite 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. HALO Network coverage

22. DEVELOPMENTS IN CONCEPT

23. CONCLUSION