Probabilistic spectrum assignment for QoS-constrained cognitive radios with parallel transmission capability

In this paper, we propose a multi-channel parallel transmission mechanism for channel assignment in cognitive radio (CR) networks. The proposed mechanism enables secondary users (SUs) to effectively utilize the spectrum while limiting the disruption rate at both SUs and primary users (PUs). The main novelty in our mechanism lies in considering the randomness of link-quality conditions and lifetime durations of idle channels to provide a statistical performance guarantee for SUs. This consideration results in improved spectrum utilization. Specifically, our mechanism attempts at minimizing the required spectrum resources for SU transmissions subject to minimum rate demand and minimum success probability requirements. Simulation results indicate that our proposed assignment satisfies the performance requirements at SUs. Results also show that utilizing the parallel transmission capability of CRs while considering the randomly time-varying nature of their operating environment allows for higher spectrum utilization and more energy saving.