This dissertation presents a retrial queueing system with finite sources designed to simulate cognitive radio networks. The model incorporates two non-independent frequency bands dedicated to serving two user classes: Primary Users (PUs) and Secondary Users (SUs). Specifically, priority queueing is applied to the PUs, while SUs are assigned an orbit-based service unit. The study employs simulation techniques to showcase the impact of inter-event time distribution on the first and second moments of response times, offering several sample examples. Additionally, various case study scenarios are explored, incorporating real-life challenges such as server non-reliability, customer abandonment, and reneging.