Overlay Secondary Spectrum Sharing with Independent Re-attempts in Cognitive Radios

TL;DR

This paper models secondary spectrum sharing in cognitive radios with independent retrial attempts, analyzing how retrial behavior affects system performance like blocking and throughput.

Contribution

It introduces a CTMC model incorporating independent retrials for secondary users in multi-channel cognitive radio networks, which was not previously analyzed.

Findings

Retrial behavior significantly impacts blocking probability.

The model provides insights into throughput optimization.

Numerical results demonstrate the effectiveness of the proposed scheme.

Abstract

Opportunistic spectrum access (OSA) is a promising reform paradigm envisioned to address the issue of spectrum scarcity in cognitive radio networks (CRNs). While current models consider various aspects of the OSA scheme, the impact of retrial phenomenon in multi-channel CRNs has not yet been analyzed. In this work, we present a continuous-time Markov chain (CTMC) model in which the blocked/preempted secondary users (SUs) enter a finite retrial group (or orbit) and re-attempt independently for service in an exponentially distributed random manner. Taking into account the inherent retrial tendency of SUs, we numerically assess the performance of the proposed scheme in terms of dropping probability and throughput of SUs.