Practical Error Bounds of Empirical Models at VHF/UHF Bands
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Date
2016
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Abstract
Empirical path loss models are widely used to predict signal propagation behavior in an environment. In this paper, a multi-transmitter scenario was used to bound the errors of five widely used empirical propagation path loss models in predicting radio waves propagation in the UHF and VHF bands in Ilorin metropolis, Nigeria. A drive test was conducted using a dedicated Agilent N9342C spectrum analyzer along seven different routes that span urban and open areas. Three transmitters were utilized in the campaign (National Television Authority NTA Ilorin, Harmony FM and Unilorin FM). The prediction error, root mean square error (RMSE), skewness of the error distribution and the relative error were further computed and presented. Furthermore, the performance of the models were also cor-related with their design parameters and constraints. The analysis reveals that, of the five models investigated, the error bounds of the ECC model is very high, hence its accuracy for Ilorin terrain, while the three models of Cost-231, Hata and Ilorin (a localized model) were below the acceptable tolerable values for the metrics used and the Egli model falls within a reasonable range of the acceptable values of 6-7dB for urban areas and 10-15dB for Suburban and rural areas. For example, while the ECC model recorded RMSE values of 54.11dB, 52.23dB and 52.41dB for the three transmitters, the corresponding values for the Hata model were; 7.9 dB, 8.37 dB and 10.13 dB, for the COST 231 model: 8.46 dB, 10.09 dB and 9.66 dB and for the Ilorin model, the RMSE values were; 8.51 dB, 8.50 dB and 10.57 dB. The RMSE values obtained for the Egli model are 16.77 dB, 14.50 dB and 10.90 dB respectively. Finally, it was found that the error distribution for each model followed the terrain profile of the routes.
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Error bound, path-loss, VHF, UHF, Ilorin Model