Optimization of Okumura-Hata Model for Long Term Evolution Network Deployment in Lagos, Nigeria

Abstract

The prediction of the signal strength received at a particular location is of paramount importance in the determination of overall performance of any wireless system. This prediction depends on the propagation path loss between the base stations and the mobile user. Some of the existing propagation path loss models such as Free Space, Okumura, Okumura-Hata, Cost231 Hata, Davidson-Hata are not suitable for prediction of Long Term Evolution signal in Lagos, Nigeria due to high error caused by higher carrier frequency and distance. Therefore, there is need to optimize these models for their suitability to LTE signal in Lagos, Nigeria. In this paper, suitability of Okumura-Hata model is investigated for LTE signal. The received signal strengths at different locations for three (3) LTE stations in Lagos are taken through the drive test. The analysis of Okumura-Hata model is carried out and compared with the measured values. Okumura-Hata is then optimized using the Least Square method. The performance of the model is evaluated using Root Mean Square Error (RMSE) to determine the path loss. The results obtained show that the RMSE is reduced from 13.46 to 0.63. This shows that the optimized model has proved to predict the path loss with improved accuracy of 23 – 28%. Therefore, the optimized Okumura-Hata model values are in agreement or higher than the measured values and can be suitably used for predicting the signal attenuation of LTE in Lagos, Nigeria.