Impact of Atmospheric Gases on Fixed Satellite Communication Link at Ku, Ka and V Bands in Nigeria

Atmospheric absorption accounts for a significant portion of the signal path loss on the Earth-Space link. The total atmospheric absorption due to Oxygen and water vapour on the path at Ku (12/14 GHz), Ka (20/30 GHz), and V (40/50 GHz) bands was evaluated for communication with Nigeria communication satellite (Nigcomsat1) on both uplink and down link at 0.01 % unavailability of an average year. Among the basic input climatic data used are monthly and yearly mean meteorological parameters of surface and vertical profiles of pressure, temperature, and relative humidity obtained from recent measurement from space by the Atmospheric Infrared Sounder (AIRS) instrument on NASA’s Aqua spacecraft for the period 2002 to 2009. International Telecommunication Union Radio Propagation Recommendation (ITU-RP 676, 2009) procedure was used for the computation of gaseous attenuation for each of the 37-stations in Nigeria. Attenuation values were obtained for both uplink and downlink frequencies, at Ku, Ka and V bands, total atmospheric absorption was determined to be between (0.11 to 0.24) dB, (0.7 to 1.1) dB and (0.82 to 3.1) dB for Ku, Ka, and V bands respectively. Contour maps showing consistent signal absorption due to Oxygen generally higher in the Southwestern region and water vapour attenuation higher in the South-southern part of Nigeria are presented.