Satellite coverage in urban areas using unmanned airborne vehicles (UAVs)

In case of emergency, when fixed infrastructures collapse, access to satellite resources might represent the only means of communication, even though, especially in an urban environment, shadowing can strongly reduce the visibility time. In addition, TCP based applications suffer from well know problems due to long latency. To improve performance we can act both at the architectural and protocol level. This paper considers an innovative architecture using HAPS (high altitude platforms station)/UAV connected to the satellite, thereby reducing the impairment of shadowing and introducing a short-range link with the user terminal; efficient TCP solutions allow use of standard equipment and applications without sacrificing performance. The combined use of both can greatly improve overall performance. The paper investigates how this innovative system architecture can be usefully employed in critical scenarios and provides a performance evaluation of TCP based applications using high data rate links.