Modified ITU-R rain attenuation model for equatorial climate

Rain attenuation has become the major factor in the performance of satellite communication links due to the high rainfall rate in tropical climates. It has become the main constraint when designing the satellite communication services especially above 10 GHz. Several research evidences show that ITU-R rain attenuation model is not exactly performing well in tropical climates. Therefore, the main concern of this paper is to present a modified ITU-R rain attenuation model in tropical climates. This modified ITU-R rain attenuation model has been implemented based on the measurement of 3 years (2008-2010) data on terrestrial rainfall rate and rain attenuation in USM Nibong Tebal, Malaysia from satellite SuperBird-C. Cumulative rain rate, frequency and elevation angle are the main parameter in modifying the ITU-R rain attenuation model. A curve fitting analysis method is used to modify the existing ITU-R rain attenuation model. The coefficients of ITU-R rain attenuation model has been modified based on the measured value in tropical climates. Comparison in term of the rain attenuation prediction error is made between the modified ITU-R rain attenuation model and existing ITU-R rain attenuation model. Based from the result, the modify ITU-R rain attenuation model has reduced the attenuation prediction error. This result shows that modified ITU-R rain attenuation model has significantly improved the rain attenuation prediction error in tropical climates. Therefore the modified ITU-R rain attenuation model is suitable to implement in tropical climates sites that having the heavy rainfall rate throughout the year.