On the Determination of a Compensation Model for Rain Degraded Digital DTH Links over a Tropical Location

Ku-band satellite remains the most cost-effective distribution channel for digital television services in terms of global coverage and wide bandwidth availability. However, signal attenuation due to rain remains the bane of the reception quality and the continuous availability. In the clear-sky, the minimum signal loss between a Ku-satellite and an earth station is about 205 dB. The amount of rain rate and the site’s latitude further compound this minimum signal attenuation. Existing reported research works are mainly limited to modelling of rain-induced attenuation without porting research findings into compensation product in terms of appropriate mitigation technique. This study is aimed at developing a robust compensation model for the rain-induced digital satellite television services for an improved quality and availability of service in Nigeria, with a specific objective of determining the optimal dish size for compensating the signal attenuation on the digital satellite TV downlink. The methodology employed involves rain data collection from the International Telecommunication Union-Radiocommunication (ITU-R) worst rain zone in Nigeria. The determination of appropriate dish sizes for different parts of Nigeria was carried out. A compensation model was derived for the rain degraded DTH link; and practical dish size of 1.5 m, for 48 dBW satellite footprint, was found to be adequate for compensating Ku satellite signal attenuation, regardless of rainstorm in Nigeria.