Investigation Of Signal Degradation Due To Rain On Satellite Downlink At Ku-Band For Tropical Climate
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Date
2011-12
Authors
Nalinggam, Renuka
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Attenuation due to rain is a major concern in transmission of microwave signals. The
effect of rain attenuation is more pronounce when signals are being transmitted at higher
frequencies. Many theoretical and experimental studies of rain attenuation have been carried out
at temperate regions of the world. In the tropical regions, however, which are famous for heavy
rains, the situation is not very encouraging. This is because the data coverage for these regions
remains inadequate due to the complex and varying climatic behaviors compared to the
temperate regions. Thus, the communication systems in tropical countries is affected
unconstructively during the heavy rain season. Therefore measurement of rainfall rate and
rainfall attenuation were done in Universiti Sains Malaysia, Nibong Tebal. The cumulative
distributions of rainfall rate and attenuation derived from the measured data are presented and
compared with existing prediction models. Most of the existing prediction models do not
perform well in high rain rate regions. The comparison results were analysed to understand the
potentials and limitations of each prediction model. In order to overcome the disadvantages in
existing models, ITU-R rain attenuation model was developed. In this proposed model, the input
parameter of rain height, hR recommended by ITU-R and the determination of the power law
coefficients to calculate rain height were developed. The proposed model was compared and
tested against measurement site data and the model was applied for prediction at Nigeria, Kenya
and Papua New Guinea. The model gave a good representation of cumulative distribution with
an overall low rms for measurement sites and three different location mentioned above. Systems
that are poorly designed lead to an increase in transmission errors, or worst, to an outage in the
received signal. In order to avoid outage in the received signals, the systems for tropical regions
need to be designed using this proposed model which is purely modified based on data from
tropical countries.
Description
Keywords
Signal degradation due to rain on satellite downlink , at ku-band for tropical climate