10-08-2011, 11:28 AM
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INTRODUCTION:
The High Altitude Long Operation (HALO) network is a broad band wireless metropolitan area network consisting of HALO aircraft operating at high altitude and carrying an airborne communication network hub and network elements on the ground. The HALO network will be located in the atmosphere, at altitude miles above terrestrial Wireless, but hundreds to thousands of miles below satellite networks. It will provide broad Band services to business and small offices in an area containing a typical large city. The HALO network infrastructure is simple, having a star topology with single central hub. Consequently, the deployment service to the entire metropolitan area can occur in the first day The network deployed and subsequent maintenance cost is expected to be low. The system Capacity can be increased by decreasing the size of beam spots on the ground while increasing the number of beams with in the signal foot print or by increasing the signal bandwidth beam
THE SYSTEM ARCHITECTURE OF THE HALO NETWORK
As shown in below fig. the HALO/Proteus aircraft servers as the hub of the wireless broad band Communication network .It carries the borne network elements including an ATM switch Spot beam antennas, and multi beam antennas, as well as transmitting and receiving electronics The antenna array provides cellular like coverage of large metropolitan area. Asynchronous transfer mode switches, now available, have capacities sufficient to satisfy the traffic volume requirements of the first network deployment and margins for growth.
The HALO/Proteus airplane shown in fig.2 has been specially designed to carry hub of the HALO Network. The airplane can carry a weight of approximately 2000lb (90 kg) to its station keeping. The airplane is essentially an equipment bus from which commercial wireless systems will be offered. A fleet of three aircraft will be cycled in shifts to achieve continuous service above an isolated city. In a multi city deployment an average of two aircraft will be allocated to each city, and the fleet operations will be conducted from a common primary flight Base as a “hub and spokes” operation to achieve continuous service. Each shift on station will have an average duration of approximately 8 hr.