Preliminary results from a physically-based methodology for the evaluation of a time diversity system

Time diversity is an advanced technique that can be employed to mitigate the detrimental effects of the atmosphere - markedly, of precipitation - on wireless telecommunication systems operating above 10 GHz. A new methodology for the simulation of an Earth-space time diversity system and for the evaluation of its performance is presented here. The proposed methodology requires as input a set of rain maps (e.g. derived by a weather radar), not necessarily correlated in time as one may expect: in fact, the rain field evolution in time is reproduced by rigidly translating rainfall structures at a constant effective velocity, whose value is scaled from the mean yearly local wind intensity, in turn derivable from global meteorological databases. As a result, when radar derived rain maps are not available, models, such as MultiEXCELL, may be employed for the generation of synthetic rain fields. Although additional tests are required, the preliminary assessment of the effectiveness of the proposed methodology in estimating the time diversity gain seems to support the assumption that the temporal evolution of the rain field can be well reproduced by introducing an effective rain field translation velocity which compensates for disregarding the deformation of rain structures in time.