Coexistence, Deployment and Business Models of Heterogeneous Wireless Systems Incorporating High Altitude Platforms
Sammanfattning: The increased demand for broadband communications has led to the rapid development of the conventional terrestrial and satellite wireless communications systems. One of the main challenges to next generation wireless systems is to deliver high-capacity and cost-efficient solutions to cope with an increasing usage of broadband services and applications. In the recent years, an emerging competitive system has attracted the attention for providing wireless broadband communications and other services based on quasi-stationary aerial platforms operating in the stratosphere known by high altitude platforms (HAPs), and located 17-22 km above the earth surface. This solution has been described by the International Telecommunication Union (ITU) as "a new and long anticipated technology that can revolutionize the telecommunication industry''. The HAP systems provide important advantages such as low cost, high elevation angles, low propagation delay, easy and incremental deployment, flexibility in operation, broad coverage, broadcast and broadband capability, ability to move around in emergency situations, etc. Therefore, they have been proposed by ITU for the provision of fixed, mobile services and applications, e.g. the third generation (3G) services licensed by ITU and backbone link for terrestrial networks in remote areas. This thesis explores and investigates the wireless communication and techno-economic performance of terrestrial systems and HAPs. An overview of research and development on aerial platforms worldwide is given. Coexistence performance and techniques of heterogeneous systems to provide broadband wireless communications based on Worldwide Interoperability Microwave Access (WiMAX) are investigated. A heterogeneous scenario is developed to examine the coexistence performance of heterogeneous systems. The capacity and deployment aspects of HAPs are analyzed, and further compared with terrestrial Universal Mobile Telecommunications Systems (UMTS) through techno-economic studies including a proposed partnership based business model for HAPs. Performance of wireless sensor network applications via HAPs is also investigated, and shows the high potential of HAPs for large-area and long-endurance surveillance and emergency applications. The thesis shows that communications from the aerial platforms provide the best features of both terrestrial and satellite systems. HAPs can effectively coexist in a heterogeneous radio environment, and are competitive solutions in urban and suburban scenarios in terms of capacity, coverage and business perspective. This makes HAP a viable competitor and complement to conventional terrestrial infrastructures and satellite systems.
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