Assessment of Seasonal Asia Monsoon Rain Impact on the Earth-Space Propagation in Equatorial Kuala Lumpur

Future satellite communication systems are moving towards high operational frequencies, typically in the Ka band (18 to 30 GHz) to deliver wider bandwidths and higher data rates in response to the increasing demand for broadband communication services and the congestion of Ku band (11 to 18 GHz). As well known, signal degradation due to rain can be a main limiting factor in this frequency band, especially in tropical and equatorial regions. Equatorial regions are characterized by wet months throughout the whole year and there is no alternation of summer and winter as in temperate regions. However, the climate in South East Asia, where Kuala Lumpur is located, is strongly seasonal because of the different monsoons caused by the changes in the direction and speed of airstreams. Hence, it is worthwhile to further assess the impact of this monsoon variation on the Earth-space propagation in this specific equatorial location. In this work, we present an extensive analysis of long-term rain attenuation statistics, focusing on seasonal variations for a Ka band satellite communication system whose ground station is located in Kuala Lumpur, Malaysia. Results originate from local drop size distribution (DSD) measurements collected by a disdrometer in the 1992-1994 periods and the usage of Synthetic Storm Technique (SST). The details on the DSD databank and on the seasonal variation of rainfall rate are briefly presented in Section 2. Afterwards, rain specific attenuation inferred from DSDs is discussed in Section 3. In Section 4, long-term rain attenuation statistics (Ka band) are predicted by means of the SST and focusing on the seasonal variation. Finally, Section 5 draws some conclusions.