Elevation-dependent channel model and satellite diversity for NGSO S-PCNs

We propose an elevation-dependent Rice-Rayleigh/lognormal channel model for communications of personal and mobile users via non-geostationary satellites (NGSO S-PCNs). Based on this channel model, we discuss the performance of satellite diversity for NGSO S-PCNs. The parameters of the channel model are derived from channel measurements, which have been carried out for different elevation angles and in different environments. The measurements indicate that the channel behaviour in NGSO S-PCNs strongly depends on the elevation angle. In order to evaluate the performance of satellite diversity we present a method which allows the modelling of two statistically dependent satellite channels. The correlation between the channel states is also derived from channel measurements and depends on the azimuth separation of the two channels and on the elevation angles. We evaluate the performance of satellite diversity for LEO and MEO systems (Globalstar and ICO) and different mobile user environments. For these systems, some crucial benefits and drawbacks of satellite diversity are discussed. It can be shown that the service availability can be significantly improved by satellite diversity.