Calculation of interference levels due to rain scatter on high-altitude platform links

The possibility of using high-altitude platforms (HAPs) in telecommunications, traffic monitoring and environmental remote sensing has attracted a lot of interest. The main reasons for this are the low implementation and deployment costs and attractive propagation characteristics of HAPs. Compared to satellites, HAPs are highly advantageous in terms of free space path loss, time delay, and ease and cost of deployment. HeliNet is a project supported by the European Union, involving several industrial and academic partners, including the University of York, with the aim of examining the feasibility of an airborne platform to support telecommunications, traffic monitoring and remote sensing applications. The main responsibility of the University of York is to assess the potential of HAPs to support broadband telecommunication services. This study explores degradation due to interference from rain scattering, which may be much worse than in LEO satellite systems in which the cells are up to 10 times larger. This is because, for a cell diameter d, in general the carrier power has a d^-2 dependence while the power received by the scattering process has a d^-4 dependence. The implications of this interference in system design are discussed