Spectrum Pooling-Based Vertical Handover for Heterogeneous Cognitive Radio Networks with QoS Constrains

Vertical handover, which often occurs in wireless mobile communication, is very important for heterogeneous wireless networks based on the cognitive radio (CR). However, a major issue is how to control vertical handover for secondary user without interfering primary user while achieving the desired quality of service (QoS) and eliminating the influence caused by hidden channel and exposed channel, simultaneously. To address this issue, this paper proposes a flexible vertical channel handover algorithm for heterogeneous cognitive radio networks. This algorithm is very flexible and effective. It can adaptively schedule channel sensing by utilizing the concept of spectrum pooling. The key QoS parameter adopted in this algorithm is channel bandwidth which denotes the heterogeneity of the networks. We evaluate the major performance metrics such as handover blocking probability, hand over cost and collision probability by simulation. The results indicate the proposed algorithm can significantly improve the performance and provide stable communication in the synchronous and asynchronous CR networks.