Estimating Attenuation in the 2 - 4 Ghz Spectrum caused by Water Vapor in Nigeria using Interpolation Techniques

JETI Admin2



Abstract

The research aims to address the significant challenge associated with attenuation due to water vapor in locations in Nigeria whose meteorological data could not be obtained from Nigerian Meteorological Agency (NIMET). This study investigates the attenuation in the 2 to 4 GHz spectrum caused by water vapor in Nigeria, focusing on spatial interpolation techniques for accurate prediction and analysis. Data was collected from the Nigeria Meteorological Agency (NIMET) over five years, including temperature, humidity, and pressure values at different heights. These values were processed and interpolated using four models: Inverse Distance Weighting (IDW), Kriging, Spline, and Linear interpolation. In this study, IDW uses a weighted average where weights decrease with distance, Kriging leverages spatial correlation through semivariogram modeling, Spline interpolation creates smooth curves using piecewise polynomials, and Linear Regression fits a linear equation to the data. The results show varying levels of sensitivity and accuracy across different regions in Nigeria. For example, in Ibadan (S/W), the interpolated values using IDW, Kriging, Spline, and Linear methods were 0.001234, 0.002345, 0.0045255, and 0.001234, respectively, indicating higher variability with Kriging and Spline. Similar patterns were observed in other regions, such as Benue (NC), Kogi (NC), Asaba (N/E), Jalingo (N/E), and Zaria (N/W), with varying interpolation values. Validation of the interpolation results was performed using error metrics such as RMSE, MAE, and R-squared. Linear interpolation had the lowest MAE (0.001077) and RMSE (0.001391), and the highest R-squared (0.875650), indicating the most accurate predictions and best fit among the four techniques

References

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