CHAPTER I
INTRODUCTION
1.1 Project Background
Attenuation has been identified as a major problem for terrestrial and satellite links beyond 10GHz. High frequency, usually higher than 10GHz mostly suffer
attenuation when facing a rainfall. The problem becomes more critical in tropical regions where there is high intensity rainfall a year. Most of terrestrial and satellite
links designed for these regions must consider the attenuation given by each condition of rainfall, so that the communication is available all the time.[1]
Determine the specific attenuation for the specific rainfall rate is very important. It is impossible to specify the accurate value of attenuation for a certain
rainfall rate; however a prediction is a best method to find the nearest and persistent attenuation value. Lots of research has been carried out in order to determine and
predict the attenuation by considering the rainfall rate, elevation angel, effective slant path length, storm and also polarization used. Thus, each research contributed its
own model for predicting the attenuation.[2] Rainfall rate statistics specified on a percent of time basis, that is the percent
of time in a year or a month that the rain rate equal or exceeds a specific value is used in the rain rate attenuation [3]. Thus, this project will gather all measurement
data in tropical region from other researcher, and predicting the attenuation given by
these data. The model of prediction which produces attenuation precisely stated by ITU-R model will be chosen as the best model to represent all the data.
1.2 Scopes of work
This project is limited to the following aspects: 1.
Literature review. Reviews on the existing research done on the rain rate attenuation prediction
all over tropical regions. The prediction model used also being discussed. 2.
Selection of appropriate data. Data will be filtered where only data from tropical region measurement is
valid. 3.
Prediction. The rain rate attenuation will be predicted by using different models.
4. Comparison.
The rain rate attenuation produces by each model will be compared to standard ITU-R for validity and consistency.
1.3 Project Objectives