No abstract

Propagation path loss exponent is an important component of system design, and knowing the values helps to avoid surprises when the actual service begins. The path loss exponent is known to be critical in establishing the coverage of any new cellular network. Estimating the path loss exponent of any environment requires raising new data sets, which can be accomplished by conducting experiments. With this objective, the present study reports the L-band signal RSS level measurements of 6 GSM base stations in the urban, suburban and rural environments of Ondo and Ekiti States in the Southwestern region of Nigeria. Using a Sony Ericsson TEMS phone monitoring device—connected to a laptop equipped with TEMS software and base station cell reference—and a GPS device, RSS measurements were performed in each sector of the base station up to 1200 m, employing a single sector verification method. The values of path loss exponents were computed from the deduced values of path loss at 50 m intervals up to distances of 1200 m. Close to the base station, the following exponent values were observed—between 2.0 and 3.8 in the urban environment, 2.0 to 2.8 in the suburban environment while for the rural environment, 1.5 to 2.6 we're observed. After the breakpoint distance, higher path loss exponent values of up to 6 was recorded in the urban environment, exponent value of up to 4.3 was observed in the suburban environment and up to 3.5 exponent value in the rural environment. It was also observed that the rural environment presented the longest breakpoint distance of 500 m. The high path loss exponents observed, especially in the urban environment, could cause GSM operators to rethink the margins they have provided. This study is useful for the design of upcoming network systems in these regions and in similar regions.

The role of propagation models in the planning of wireless network, evaluation of cell parameters and frequency assignment cannot be overemphasized. One of the major difficulties with the application of path loss predicting models for any environment is that no two environments are the same in building patterns, terrain, atmospheric conditions, etc. It is therefore impracticable to formulate a single path loss model for all environments. In this study, an assessment of microwave frequency band measurement results based on received signal strength (RSS) values from four base stations in four urban environments in Osun State, Nigeria, are presented. The measured path loss values of each base station were extracted from the RSS values and compared with the results estimated from five conventional path loss models. Model comparison results based on three metric measures and fitting accuracy showed that a log-normal shadowing model exhibited a better agreement with the measured path loss with RMSE of less than 8 dB, the lowest RE, and R2 closer to one, in all the environments monitored. The best probable probability distribution for modelling the path loss at the investigated urban environments was also determined. The result of the various distribution functions tested using three goodness of fits showed that the normal distribution function offered the best match with the path loss values based on RMSE, RE, and R2 values calculated and fitting accuracy for both environments. Practical path loss parameters were also estimated for each of the base stations considered. The overall results should be useful for planning future mobile network channels.