HAPs can be considered as a novel solution for providing telecommunications services. Haps are well established as a concept essentially they are quasi stationary vehicles in stratosphere which are generally unmanned or solar powered they can support payloads for communications relay in a similar fashion as a satellite and thence provide a range of tactical and strategic wireless services.
They are usually operating in the stratosphere at altitudes of up to 22km to provide communication services they can exploit the best features of both terrestrial and satellite schemes the platforms may be aeroplanes or airships and may be manned or unmanned with autonomous operation coupled with remote control from the ground.
HAPs have similarities and differences with terrestrial wireless and satellites systems. The most important advantages of HAPs systems are their easy and incremental deployment, flexibility/reconfigurability, low cost operation, low propagation delay, high elevation angles, broad coverage, broadcast/multicast capability, broadband capability, ability to move around in emergency situations etc,.
A very interesting feature is that for the same bandwidth allocation terrestrial systems need a huge number of base stations to provide the needed coverage, while GEO satellites face limitations on the minimum cell size projected on the earth surface and LEO satellites suffer from handover problems. Therefore, HAPs seem to be a very good design compromise.
HAPs represent an economically attractive way for the provision of communications. The cost for the development of satellite systems is much greater, and it may be economically more efficient to cover a large area with many HAPs rather than with many terrestrial base stations or with a satellite system. In addition, due to their long development period, satellite systems always run the risk of becoming obsolete by the time they are in orbit. HAPs also enjoy more favorable path-loss characteristics compared to both terrestrial and satellite systems, while they can frequently take off and land for maintenance and upgrading.
Actually, today it is very interesting and challenging to examine and evaluate a mixed infrastructure comprising HAPs, terrestrial and satellite systems, which could lead to a powerful integrated network infrastructure by making up for the weaknesses of each other Moreover, the growing exigencies for mobility and ubiquitous access to multimedia services call for the development of new generation, wireless telecommunications systems. In this respect, 4G networks are expected to fulfill the vision for optimal connectivity anywhere, anytime, providing higher bit rates at low cost, and towards this end, HAPs can play an important role in the evolution of systems beyond 3G. Among the wide spectrum of services that 4G networks are called to support, multicast services represent one of the most interesting categories. However, if Multimedia Broadcast and Multicast Services (MBMS) were to be provided by the terrestrial segment, they would lead to high traffic load.
They are usually operating in the stratosphere at altitudes of up to 22km to provide communication services they can exploit the best features of both terrestrial and satellite schemes the platforms may be aeroplanes or airships and may be manned or unmanned with autonomous operation coupled with remote control from the ground.
HAPs have similarities and differences with terrestrial wireless and satellites systems. The most important advantages of HAPs systems are their easy and incremental deployment, flexibility/reconfigurability, low cost operation, low propagation delay, high elevation angles, broad coverage, broadcast/multicast capability, broadband capability, ability to move around in emergency situations etc,.
A very interesting feature is that for the same bandwidth allocation terrestrial systems need a huge number of base stations to provide the needed coverage, while GEO satellites face limitations on the minimum cell size projected on the earth surface and LEO satellites suffer from handover problems. Therefore, HAPs seem to be a very good design compromise.
HAPs represent an economically attractive way for the provision of communications. The cost for the development of satellite systems is much greater, and it may be economically more efficient to cover a large area with many HAPs rather than with many terrestrial base stations or with a satellite system. In addition, due to their long development period, satellite systems always run the risk of becoming obsolete by the time they are in orbit. HAPs also enjoy more favorable path-loss characteristics compared to both terrestrial and satellite systems, while they can frequently take off and land for maintenance and upgrading.
Actually, today it is very interesting and challenging to examine and evaluate a mixed infrastructure comprising HAPs, terrestrial and satellite systems, which could lead to a powerful integrated network infrastructure by making up for the weaknesses of each other Moreover, the growing exigencies for mobility and ubiquitous access to multimedia services call for the development of new generation, wireless telecommunications systems. In this respect, 4G networks are expected to fulfill the vision for optimal connectivity anywhere, anytime, providing higher bit rates at low cost, and towards this end, HAPs can play an important role in the evolution of systems beyond 3G. Among the wide spectrum of services that 4G networks are called to support, multicast services represent one of the most interesting categories. However, if Multimedia Broadcast and Multicast Services (MBMS) were to be provided by the terrestrial segment, they would lead to high traffic load.
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