31-07-2012, 12:35 PM
High Altitude Aeronautical Platform Station HAAPS
[attachment=29671]
Why HAAPS ?
It combines most of the advantages of satellite and terrestrial systems while avoiding many of the pitfalls.
These are, generally, solar-powered, unmanned, remote-operated and electric motor propelled aerial platforms held in a quasi – stationary position, at altitudes between the 17 – 22 Km range above the earth’s surface (stratospheric layer of the atmosphere)
Architecture
The platform is positioned above the coverage area.
There are basically two types of HAAPS. Lighter-than air HAAPS are kept stationary, while airplane-based HAAPS are flown in a tight circle.
For broadcast applications, a simple antenna beams signals to terminals on the ground.
For individualized communication, such as telephony, "cells" are created on the ground by some beam forming technique in order to reuse channels for spatially separated users, as is done in cellular service.
Beam forming can be as sophisticated as the use of phased-array antennas .
In the case of a moving HAAP it would also be necessary to compensate motion by electronic or mechanical means in order to keep the cells stationary or to "hand off" connections between cells as is done in cellular telephony
GROUND INSTALLATIONS
The ground system in figure corresponds to the onboard equipment from the previous figure.
Carrier signals coming from the air-borne station are filtered by a BPF, amplified in LNAs, demultiplexed in the demux and passed to the CDMA base stations.
From the base stations, the signals are passed in the usual manner to the mobile switching center MSC and public switched telephone network (PSTN).
The return signal path towards the airborne station is similar except for the inverse multiplexing operation in the MUX and high power amplification by HPA.
[attachment=29671]
Why HAAPS ?
It combines most of the advantages of satellite and terrestrial systems while avoiding many of the pitfalls.
These are, generally, solar-powered, unmanned, remote-operated and electric motor propelled aerial platforms held in a quasi – stationary position, at altitudes between the 17 – 22 Km range above the earth’s surface (stratospheric layer of the atmosphere)
Architecture
The platform is positioned above the coverage area.
There are basically two types of HAAPS. Lighter-than air HAAPS are kept stationary, while airplane-based HAAPS are flown in a tight circle.
For broadcast applications, a simple antenna beams signals to terminals on the ground.
For individualized communication, such as telephony, "cells" are created on the ground by some beam forming technique in order to reuse channels for spatially separated users, as is done in cellular service.
Beam forming can be as sophisticated as the use of phased-array antennas .
In the case of a moving HAAP it would also be necessary to compensate motion by electronic or mechanical means in order to keep the cells stationary or to "hand off" connections between cells as is done in cellular telephony
GROUND INSTALLATIONS
The ground system in figure corresponds to the onboard equipment from the previous figure.
Carrier signals coming from the air-borne station are filtered by a BPF, amplified in LNAs, demultiplexed in the demux and passed to the CDMA base stations.
From the base stations, the signals are passed in the usual manner to the mobile switching center MSC and public switched telephone network (PSTN).
The return signal path towards the airborne station is similar except for the inverse multiplexing operation in the MUX and high power amplification by HPA.