Cognitive radio-enabled QoS-enhanced scheme for IEEE 802.16e networks

The IEEE 802.16e network faces the challenge of bandwidth shortage due to the growing demand for high-bandwidth applications. One promising approach is to obtain bandwidth by using cognitive radio (CR) technology, which provides an effective way to achieve incremental bandwidth from unlicensed spectrum. However, the appearance of primary users (PUs) does harm to the performance of secondary users (SUs). In this paper, we propose a QoS-enhanced scheme to prevent real-time services in 802.16e networks from corruption when switching between licensed and unlicensed bands. Adaptive bandwidth reservation mechanism and simplified switch mechanism are proposed to improve QoS performance for 802.16e services. Finally, simulation results show that our scheme has lower connection dropping probability (CDP) at a reasonable cost of connection blocking probability (CBP) than conventional scheme.