GSM Broadband Coverage Analysis Under Rainy Environments

Abstract

The path loss due to rainfall affects the radio coverage of GSM broadband. With the higher value of frequency and rainfall rate, the specific path attenuation increases, which significantly changes the coverage area as well as the handoff parameters of the GSM (Global System for Mobile Communications) broadband service. Though the significant change in signal level is seen above 6 GHz frequency, the signal level changes in lower bands such as 900 and 1800 MHz are also measurable. The 5G services are allocated with different frequencies ranging from 600 MHz to 60 GHz (Spectrum Allocation for 5G International Framework, ITU Regional Economic Dialogue on Information and Communication Technologies for Europe and CIS (RED-2019), Odessa, Oct 2019), where the effect of rainfall will be severe for higher frequencies. The ITU-R P.838-2 recommendation (Specific attenuation model for rain for use in prediction methods, RECOMMENDATION ITU-R P.838-2 (1992–1999–2003)) defined the relationship between specific path attenuation and rainfall rate and also defined the values of coefficient α of R for different frequencies. This paper is mainly focused on the evaluation of k-R relationship for 900 MHz (2G) and 1800 MHz (4G) frequency bands using simulation and experimental measurement-based approaches and simulation of all proposed 5G and WiMAX (Worldwide Interoperability for Microwave Access) frequency bands. The measurement of signal levels for path loss calculation of 900 and 1800 MHz is performed using two mobile sets and rain gauge in urban area of Bhaktapur city. The simulated and measured path loss values are compared with the ITU defined values for validation. The results of simulation and practical measurement have shown that for the 900 MHz frequency, the specific path attenuation is not significant compared to the 1800 MHz. Also, for 5G frequency bands and WiMAX, the specific path attenuation of higher frequencies is found to be significantly larger and can be the major cause for service termination. So, the signal loss due to rainfall shall be considered during the coverage planning and assigning handoff parameters of higher 5G frequency bands.