Tropospheric Influence on Call Setup in Mobile Networks

Abstract

The dependency of mobile network operators on the troposphere for signal transmission without pre-evaluation and characterization of the region where the signals are transmitted is the reason for the poor Quality of Services (QoS) delivered to their network subscribers. To describe the reliability of networks, one needs to know which weather parameters affect the propagation of signals. This research investigates the effect of weather variables (relative humidity, wind speed, rainfall and temperature) on call setup for four mobile networks (MTN, Airtel, Globacom and 9mobile) in Cross River State, Nigeria. Six years data of weather variables collected from the Nigerian Meteorological Agency (NiMet) and six years Call Setup Success Rate (CSSR) data obtained from the telecommunications regulatory body, Nigerian Communication Commission (NCC), was used in this study, both spanning from January 2015 to December 2020. From the collected data, graphs were plotted and, in each case, the CSSR was the dependent variable while the tropospheric variables were the independent variables. Also, regression models were obtained to forecast the CSSR of each network, provided the tropospheric variable at each given period is known. Finally, the variables were correlated to give a picture of how each tropospheric variable related to the CSSR of the networks. For MTN network, a low negative correlation was obtained for temperature and relative humidity, a low positive correlation was obtained for rainfall while an increase in windspeed led to a corresponding decrease in CSSR. For Airtel network, a moderately positive correlation existed between CSSR and windspeed/rainfall while a low positive relationship existed between temperature and CSSR. However, an increase in relative humidity led to more successful call setups. For Globacom network an increase in relative humidity, windspeed, and temperature moderately led to a decrease in the number of successful call setups while rainfall had a very low effect on call setup. Finally, for 9mobile network, an increase in temperature led to a moderate increase in call setup. Relative humidity and windspeed had a negligible effect on call setup while a moderately negative relationship existed between rainfall and call setup. The result of this study will be very useful to mobile network planners and the network operators.