认知异构无线网络中可信频谱切换机制

在认知异构无线网络中，针对频谱切换过程中次用户发生自私或恶意行为，导致网络性能下降的问题，提出一种基于信誉系统的频谱切换机制。通过提取用户行为特征信息，评估次用户接入信道后的行为，并依据次用户的行为确定其信誉值，在认知基站建立信誉系统。根据次用户的信誉状况来对次用户进行分级，并根据分级情况，为次用户分配授权信道或共享频段的信道。在可信次用户接入授权频谱的过程中，当满足用户等待时延要求时，信誉值高的次用户有更高的接入优先权。可疑次用户可以在共享频段中进行传输。仿真结果表明，算法能够有效地提升系统吞吐量，降低切换及中断概率，减少低信誉次用户接入授权频谱的机会，提升了系统的安全性。

Trusted spectrum handoff mechanism in cognitive heterogeneous wireless networks

In cognitive heterogeneous wireless networks, a spectrum handoff mechanism based on reputation system is proposed. This mechanism is to solve the problem of network performance degradation caused by selfishness or malicious behavior of secondary users in spectrum handoff. Firstly,by extracting the user characteristic information,the behavior of the secondary users after accessing the channel is evaluated. According to the behavior of the secondary users,the reputation is calculated, thereby establishing a reputation system in the cognitive base station. Then, the secondary users are ranked according to the reputation status, and the licensed channels or channels of the ISM band are allocated to the secondary users according to their ranking. In the process of accessing the licensed spectrum,when the trusted user meets waiting delay requirement,the secondary user with a high reputation value has a higher access priority.Suspicious secondary users can transmit in the ISM band.Simulation results show that the proposed method can effectively improve the system throughput,reduce the handoff and interrupt probability, reduce the chance of low-reputation secondary users to access the licensed spectrum, and improve the security of the system.