CHANNEL MODELING FOR BEYOND-5G COMMUNICATIONS

Abstract

The thesis aims to study channel modeling for beyond fifth generation (B5G) communications. The terahertz (THz) frequency band is closely related to B5G technologies as it provides a higher data rate and a large range of frequency values for the signal propagation. The limitations of THZ communications are that signal propagation can be heavily influenced by the free space propagation loss and molecular absorption loss due to the high frequencies. Thus, the papers suggest implementing reflective intelligent surfaces (RISs) assisted system models to enhance the signal quality and avoid disruptive communication due to possible blockages in the transmission path. Moreover, the paper suggests using the approximation for the RIS link to decrease the computation complexity, which can be caused by the increased number of RIS elements. Here, the THz communication is accurately described by the α-µ distribution, and it is used for modeling fading channels. An approximated RIS link is further applied to an underlay cognitive radio (CR) system. As a result, the performance metrics, such as outage probability, are derived analytically and compared with simulation results. The resulting outage probability with α-µ fading channels only works for fixed regions of the system parameters. The thesis also considers the Gamma distributed fading channels since it is simpler compared to the α-µ distribution to derive a more generic expression for outage probability.