Frequency bands allocated to mobile communication are limited and therefore a scarce resource. Due to the increasing number of user equipment having communication capabilities, the prices of spectrum licenses have steeply increased in recent years. This requires large investments from the mobile network operators and ultimately increases the subscription prices of consumers. Simultaneously, there are great opportunities with technologies such as machine-to-machine communication and internet-of-things, which often do not require long-distance, high bit-rate communication.

The practical implementation as a part of this thesis studies the interference caused by device-to-device (D2D) communication performed simultaneously on a shared frequency band with conventional 5G mobile communication. The purpose of this work is to identify the applicability of such a technology allowing dynamic spectrum access together with risk based interference management. Based on the results, guidelines for the D2D communication regulation will be considered.

The research is done by employing a computational simulation for a group of devices performing device-to-device communication. Additionally, ray-tracing software is being used to calculate signal propagation path loss between the devices and base stations being exposed to the interference. Different scenarios are considered as case studies to understand the opportunities for D2D links. By applying methodology of risk-informed spectrum management, the possible risks of the scenarios can be identified based on the results. Moreover, the techno-economic aspects of the direct D2D communication is being discussed, introducing scenarios where D2D communication could be applied.