Slant path rain attenuation comparison of prediction models for satellite applications in Malaysia

A 2-year campaign of slant path rain attenuation measurements has been carried out in Malaysia using the Superbird-C satellite beacon at 12.255 GHz. The rain intensity time series have been recorded with a conventional tipping-bucket rain gauge located at the station, during a continuous observation period spanning the same 2 years of the beacon measurements. The experimental cumulative distributions of rainfall rate and rain attenuation are presented. Two years of rain attenuation measurements at 12.255 GHz shows high values that have been detected for small percentage of time; for example, the attenuation exceeded 25 dB for 0.01% of time. The rainfall rate is compared with International Telecommunications Union-Radiocommunication (ITU-R) maps, and the measured rain rate distribution is close to that derived from the ITU-R maps. Measured rain attenuation values are compared with several prediction models. A good agreement has been found in the comparison of the experimental distribution with some prediction models (Ramachandran, Bryant, Matricciani, and Exponential Cell (EXCELL) with percentage errors below 11%) calculated using the measured rainfall rate distribution. The lack of rain measurement data from equatorial and tropical regions for verification causes predictions obtained from existing models to deviate from direct measurements.