Thesis (D.Eng.)--Chulalongkorn University, 1997

To concentrat on the study of 12 GHz rain attenuation along an earth-satellite path and point-rainfalll intensity in Southeast Asia using the data from the "Canada-ASEAN Cooperation in the Ku-band Propagation Measurement Progam on Earth-space Paths". Three years of measured data in Indonesia, Singapore, and Thailand were analyzed to obtain the knowledge of rain attenuation and rainfall intensity characteristics. The knowledge from these analysis are applied to develop a powerful model to predict fade-duration statistics and rain attenuation distribution at least every 2 hours of the day that has never been reported before. Results of 24-year-data study can be summarized as follows: 1) the measured cumulative distributions of rain attenuation over a three-year period between February 1992 and March 1995 in Southeast Asia disagree with all prediction models, but the log-normal distribution proves to be more reasonably fitted to data of all experimental sites, 2) the measured cumulative distributions of rain intensity agree very well with the negative exponential distribution, 3) the fade duration distributions fit very well with the double exponential distribution, 4) the diurnal variations of rain attenuation statistics at all locations are well correlated with one-hour rainfall statistics, 5) the new model that predicts rain fade every two hours utilizing the knowledge of the diurnal variations statistics of rain attenuation and rainfall associated with the log-normal distribution, was developed and evaluated. Finally, it is found very useful for the design of Ku-band satellite communication system especially in the heavy rainfall regime of Southeast Asia.