Micro rain cell measurements in tropical India for site diversity fade mitigation estimation

Intersite separation (ISS) between two terminals is one of the important parameters required for implementation of site diversity (SD), as a fade mitigation technique (FMT), in moderate to heavy rain conditions usually encountered in tropical climates. This paper presents the findings of an experiment during the monsoon periods of years 2007 and 2008. It establishes the existence of micro rain cell (MRC) at a tropical site, Ahmedabad (23.06°, 72.62°), India, using measurements from tipping bucket rain gauge network. Spatial extent of MRCs and derived attenuation cells is examined on the basis of their maximum occurrence for initial to mid and last spells of years 2007 and 2008. The analysis also presents ISS statistics of monsoon periods for both the years. Microscale SD as FMT has been discussed on the basis of the calculated diversity gain at K_a band frequency in view of the proposed GSAT-4 satellite. These are the very first findings of their kind over the region of study.