Opportunistic Spectrum Sharing with Quality-of-Service Support in Cognitive Radio Networks

Opportunistic spectrum sharing (OSS) has become an effective method to fully utilize the scarce spectrum resources. In this paper, we propose an OSS scheme with quality-of-service (QoS) support for secondary users (SUs) in cognitive radio networks (CRNs). SUs are classified into the SUs with real-time traffic (RT-SUs) and the SUs with non-real-time traffic (NRT-SUs). The RT-SUs have higher terminated-priority than NRT-SUs to guarantee the QoS requirements of RT-SUs. If a primary user (PU) tries to access the channel used by an RT-SU or a NRT-SU, the RT-SU can be terminated only when there is no idle channel, while the NRT-SU has to stop its transmission. We also use a random probability function to control the channel access of the SUs so that second users can achieve different successful access probability according to their payment. In addition, we use a six-dimensional Markov approach to derive system performance in terms of forced termination probability, blocking probability and system throughput for RT-SUs and NRT-SUs with different access-priorities. Numerical results show that the proposed scheme can meet the QoS requirements of different SUs in the presence of guaranteeing the communication quality of PUs and achieve great throughput improvement compared to typical spectrum sharing schemes.