PSHO-HF-PM: An Efficient Proactive Spectrum Handover Mechanism in Cognitive Radio Networks

In the paper, we develop an efficient proactive spectrum handover mechanism by using packet scheduling algorithm, called PSHO-HF-PM, to reduce unusable channel. It effectively integrates several mechanisms (hole filling and packet migration) to reduce the bandwidth fragment and support QoS. Its basic idea is in that a new packet is scheduled by migrating some packets to other channels if none of holes in any channels can accommodate it; otherwise repeating the above processes after random waiting time. Meanwhile under an effective data structure, such as the balanced binary search tree, its computational complexity will be at most. In the proposed packet scheduling algorithm, packet migration plays a key role in the improvement of bandwidth efficiency and QoS. We also evaluate the performance of total service time for proactive spectrum handover mechanism based on a Preemptive Resume Priority M/G/1 queuing network model. The performance analysis and simulation results show that it performs much better than other proactive and reactive handover mechanism in collision rate, total service time, packet loss probability and bandwidth fragment ratio.