认知无线网络中的频谱切换性能分析

在认知无线网络中，次用户的频谱切换性能不仅和主用户的通信行为关系密切，而且也和次用户本身的频谱感知精度以及频谱切换策略密切相关。该文采用连续时间马尔科夫模型对次用户在理想感知和非理想感知情况下的频谱切换进行建模，进一步分析与比较不同频谱感知精度对频谱切换性能的影响。为了有效降低次用户在频谱切换过程中的强制中断概率，提出基于信道预留机制的频谱切换策略。数值结果表明，次用户对主用户信号的感知精度明显会影响次用户的频谱切换性能，而有效的频谱切换策略则可以以较小的代价获得更好的频谱切换性能。

Performance Analysis of Spectrum Handoff in Cognitive Radio Networks

In cognitive radio networks, the spectrum handoff performance of secondary users not only relates closely to the communication behavior of primary users, but also related closely to the spectrum sensing accuracy and the spectrum handoff strategies of the secondary users. In this paper, the spectrum handoff schemes that considered with perfect sensing and imperfect sensing are modeled by using the continuous time Markov model, and the affection on the performance of spectrum handoff for different spectrum sensing accuracy is analyzed and compared further. Furthermore, the spectrum handoff strategy based on the channel reservation mechanism is proposed to reduce the forced termination probability of the secondary users effectively in the spectrum handoff process. The numerical results show that the sensing accuracy on the primary signals affects significantly the spectrum handoff performance of secondary users, while the effective spectrum handoff strategy can achieve better performance for spectrum handoff at a lower cost.