Predictive Analysis of Rain Fade Duration on Ku-Band Satellite Links in Southwest Nigeria

This paper examines the effects of rain fade on Ku band satellite communications in Southwest Nigeria. Ku band systems (12-18 GHz) are susceptible to rainfall, which can degrade signal quality and disrupt links. Data from six states (Ekiti, Lagos, Ogun, Ondo, Osun, and Oyo) were analyzed over a 10-year period using the Moupfouma and Martins model to determine the rain rate, and ITU-R models to predict specific attenuation (dB/km), total attenuation (dB), effective path length (km) and fade duration for vertical, circular, and horizontal polarizations. Results showed that Oyo state had the least attenuation (8.86-16.95 dB) and the longest effective path length (4.64-4.49 km), while Lagos had the highest attenuation (9.75-18.47 dB) and shortest effective path length (4.56-4.42 km) due to higher rain rates from its coastal proximity. Despite differences, all states experienced attenuation below the critical 20 - 30 dB outage threshold for Ku band signals. Furthermore, fade events lasted for short periods, typically 1 second, with Lagos state having the highest fade event occurrences, while Oyo state had the fewest. An average time of fade events was 10 s and below 500 events per annum. The paper recommended a fade margin of 15-25 dB to maintain transmission reliability in the region. It also suggested that engineers account for varying attenuation and fade duration specific to each state when designing satellite communication systems.