Analysis of roof-to-street propagation for fixed broadband wireless access

Fixed Wireless Access (FWA) is an alternative solution to fiber that leverages mobile wireless technology to deliver internet connectivity to the final user in an affordable way. Now, with the advent of 5G New Radio (5G NR), The FWA capabilities can be fully exploited bringing several advantages, much more than before. When dimensioning a FWA network, two meaningful factors must be considered: the received power at CPE side and the estimation of the signal attenuation. In order to identify the best place where to locate the equipment, a detailed analysis is needed to investigate how the signal propagates and interacts with the radio environment, thus propagation models help us to achieve this important goal. Nowadays, several models of different kind and complexity have been studied and developed with the common assumption that the user equipment is at street level. Unfortunately, this restriction is not suitable for FWA commercial applications, since the receiving antenna should be placed higher than ground level for a good reception for both indoor and outdoor places, therefore it is necessary to tune these models for a more flexible analysis. The present work has statistically assessed the roof-to-user correction factor, here called floor gain factor, to take into account the actual placement of Customer Premise Equipment (CPE) with respect to the ground level. In particular, we provide the proper adjustment to propagation models at different heights from the ground, in order to have the right prediction of signal attenuation, in the 3.6 GHz frequency band. In addition, a physical-statistical model has been developed in order to is to validate empirical data and to support the analysis, offering the opportunity to examine each single ray and see how radio propagation mechanisms work in the roof-to-street (RTS) case.