Cognitive radio can significantly improve the spectrum efficiency, and spectrum handoff is considered as an important functionality to guarantee the quality of service (QoS) of primary users (PUs) and the continuity of data transmission of secondary users (SUs). In this paper, we propose an analytical framework based on a preemptive repeat identical (PRI) M/G/1 queuing network model to characterize spectrum handoff behaviors with general service time distribution of both primary and secondary connections, multiple interruptions and transmission delay resulting from the appearance of primary connections. Then, we derive the close-expression of the extended data delivery and the system sojourn time in both staying and changing scenarios. In addition, based on analysis of spectrum handoff behaviors resulting from multiple interruptions caused by the appearance of the primary connections, we investigate the traffic-adaptive policy, by which the considered SU will optimally adjust its handoff spectrum policy. Moreover, we investigate the admissible region and provide the reference for designing the admission control rule for the arriving secondary connection requests. Finally, simulation results verify that our proposed analytical framework is reasonable and can provide the reference for executing the optimal spectrum handoff strategy and designing the admission control rule for the SU in cognitive radio networks.
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机译：认知无线电可以显着提高频谱效率，频谱切换被认为是保证主要用户（PU）的服务质量（QoS）和次要用户（SU）数据传输连续性的重要功能。在本文中，我们提出了一个基于抢先重复相同（PRI）M / G / 1排队网络模型的分析框架，以通过主要和次要连接的一般服务时间分布，多个中断和传输延迟产生的频谱切换行为来表征频谱切换行为。主要连接的外观。然后，我们得出扩展数据传递的封闭式表达以及系统在停留和变化情况下的停留时间。另外，在分析由主要连接的出现引起的多次中断导致的频谱切换行为的基础上，我们研究了流量自适应策略，通过该策略，所考虑的SU将最佳地调整其切换频谱策略。此外，我们研究了允许区域，并为设计到达的辅助连接请求的接纳控制规则提供了参考。最后，仿真结果验证了我们提出的分析框架是合理的，可以为执行最佳频谱切换策略和设计认知无线电网络中的SU的接纳控制规则提供参考。
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