Algorithmic Analysis of Cognitive Multichannel Retrial Network System With Finite-Source Primary Users and Admission Control for Secondary Users

This research article explores a novel category of multichannel cognitive radio (CR) wireless retrial queueing network. The channels (radio spectrums) are shared between secondary users (SUs) and primary users (PUs), with PUs enjoying preemptive priority. The PUs are originated from a finite number, $N$, of identical sources. In addition to PUs holding absolute priority over SUs, the impact of repeated attempts of PUs has been implemented. To optimize radio spectrum utilization and improve transmission quality, a waiting line buffer for SUs is deployed. For this intricate system, the ergodic condition and joint stationary probability distribution of SUs and PUs are derived using matrix-geometric methods. Various essential performance metrics of the system have been evaluated. Additionally, vital probabilistic descriptors, including successful, vain, and ideal retrials, are thoroughly examined in the context of the CR wireless network. By exploring the first-step principle, the first-passage time to attain a specific critical level in the waiting line buffer of SUs and associated average measures are discussed. Finally, comprehensive numerical results and graphical analyses are presented to provide insights into the proposed scheme.