Abstract:
Satellite communication has become an important part for the fast and cheap communication around the globe. Almost all of our communications including TV broadcasting, telephone system, forecast and especially for the military purposes are carried out through Satellite communication.
But to achieve this, there are major factors that disturb the satellite communication through ground station. Some of them are Atmospheric Absorption, Cloud Attenuation, Ionosphere Scintillation, and Rain Attenuation. In Geo stationary satellite, these factors play major role at the edges of the coverage area of the earth where the elevation angle from the ground station is very small; in such a situation, satellite communication gives a challenging environment.
Pakistan is among those countries which have their own satellite in the Geo stationary orbit. Pakistan's satellite (PAKSAT-1R) is at 38° east and hence the elevation angle from ground station is acute. This satellite has a total of 30 transponders, 12 in C-band and 18 in Ku-band. For last few years, excess rain and fog in different areas has affected satellite communication. This situation leads to a necessity of estimating the attenuation produced by these environmental disturbances. A model proposed by IUT-R is used for this task but it has many limitations and does not perform well in all areas.
This thesis would focus on the Ku-band communication in the three areas (Islamabad, Lahore & Karachi) of Pakistan because PAKSAT-1R operates only from these areas. The purpose of selection of Ku-band is due to the fact that communication is affected by rain and fog at frequency above 10 GHz. Data of rain, fog and atmospheric temperature have been collected from different stations of Meteorological department in proposed study areas for the last 10 year on monthly bases.
Attenuation in area under study will calculated on different values of rain and fog by using
different Rain attenuation models. A correlation analysis will be performed to check the degree of dependence of attenuation on rain and fog. Validity of IUT-R model will be tested by comparing the values of attenuation with different models.
Hence the entire research work is based on comparing the attenuation calculated by different models on different location of Pakistan for the last 10 years. The analysis will be performed to check and compare ITU-R attenuation model with other models in use. The research will be very helpful in future to formulate an attenuation model specifically for region of Pakistan. And also help the satellite operating agencies to made decisions in the rainy and fogy seasons about the increase or decrease in transmitting power.
