Rain fade characteristics at Ku- and Ka-bands in some parts of Nigeria

Abstract

Rain fade characteristics at Ku- and Ka-bands in parts of North-eastern (Damaturu, Bauchi and Maiduguri) and South-western (Abeokuta, Ibadan and Ikeja) regions of Nigeria is presented in this work. 33 years (1983-2015) rainfall data were collected from the Nigerian Meteorological Agency (Nimet) for the locations. Chebil rain rate model was used to compute the point rainfall rate, while ITU-R P.618-12 model was used to compute the rain-induced attenuation at frequencies of 11 GHz, 14 GHz, 20 GHz, and 40 GHz. Point rainfall rate of 85.24 mm/h, 98.20 mm/h and 99.30 mm/h were obtained at Damaturu, Maiduguri and Bauchi respectively, while higher rainfall rate of 99.70 mm/h, 104.8 mm/h and 108.20 mm/h, were recorded at Abeokuta, Ibadan and Ikeja respectively. Three elevation angles were considered: 23o , 42.5o and 55o . The results obtained show that rain-induced attenuation for the Southwestern region varied from 20.56 dB to 41.00 dB at 23o elevation angle, 12.85 dB to 26.44 dB at 42.5o elevation angle and 10.61 dB to 22.34 dB at 55o elevation angle at Ku band, while the rain-induced attenuation computed for the Northeastern region varied from 18.59 dB to 37.65 dB at 23o elevation angle, 11.61 dB to 23.46 dB at 42.5o elevation angle and 9.59 dB to 20.52 dB at 55o elevation angle for exceedance time percentage of 0.01% at Ku-band. For the Ka-band, the rain-induced attenuation for the Southwestern region ranged between 59.71 dB and 183.75 dB at 23o elevation angle, 40.39 dB and 133.48 dB at 42.5o elevation angle and 35.12 dB and 122.11 dB at 55o elevation angle, while the rain-induced attenuation computed for the Northeastern region ranged between 54.06 dB and 168.97 dB at 23o elevation angle, 36.50 dB and 120.79 dB at 42.5o elevation angle and between 31.71 dB and 111.76 dB at 55o elevation angle for same 0.01 percentage of time exceedance.