Prediction of Rain Attenuation in Malaysia Using TRMM Data

Rainfall is observed as a main contributing factor in the degradation of electromagnetic signal for frequency above 10GHz through absorption and scattering, resulting a weak or fading signal. Broadcasting satellite service operates in Ku band (12GHz to 18GHz) is widely used has caused congestion, therefore Ka band is exploited to meet the customer demand. However, the rain attenuation effects on Ka band are higher than Ku band. In this study, the rain attenuation effects of Ka band downlink signal of the Measat-5 satellite are analysed to assess the rain fade properties using TRMM 3B42 data for eleven (11) years from January 2009 until December 2019 for fourteen study areas. All data are processed to obtain 1-minute integration data using Segal Model and the prediction of rain attenuation are implemented using ITU-R P.618-13 model. This study summarizes, there are three, (3) main factors that influence the impact of rain attenuation, namely the value of specific attenuation, receiver station altitude and elevation angle of the satellite signal receiver antenna. The signal availability impact on rain attenuation shows, eight (8) study areas could receive 99.90% of service readiness, while the rest at 99.00% to comply with the ITU unavailability requirements. Overall, the value of rain attenuation on the West Coast of Peninsular Malaysia is smaller than the East Coast of Peninsular Malaysia and the value of rain attenuation in the East Coast of Peninsular Malaysia is closer to the value of rain attenuation in Sabah and Sarawak.