一种行为信任模糊评估模型

针对认知无线电网络中反馈虚假频谱信息和强占频谱资源的恶意行为,提出一种行为信任模糊评估模型.把频谱感知行为和频谱使用行为作为两个评价因素,基于信任的主观性和不确定性使用模糊综合评判决策方法构建节点的信任评价.在合作频谱感知中,基于综合评判结果识别恶意节点以消除虚假反馈信息;在频谱分配中,使用模糊集合之间的格贴近度定义,计算实际综合评判集与理想综合评判集之间的差异,以此量化非恶意节点的可信程度,并结合多目标优化算法确定分配给节点的频谱资源.以上机制抑制了节点的恶意行为,激励了节点的合作行为,实现了物理层的频谱感知和MAC层的频谱分配的联合设计.仿真结果及分析表明,在恶意攻击下,该模型较已有模型在系统的感知性能、吞吐量和频谱分配的公平性方面都有较好的表现.

Behavior trust fuzzy evaluation model

To cope with malicious behavior in cognitive radio networks such as providing false spectrum information and seizing spectrum resources, this paper proposes a behavior trust fuzzy evaluation model. With spectrum sensing behavior and spectrum utilization behavior as two evaluation factors, this model implements nodes' trust evaluation using the fuzzy comprehensive evaluation and decision method based on subjectivity and uncertainty of trust. In cooperative spectrum sensing, this model identifies malicious nodes based on the result of comprehensive evaluation to eliminate false feedback. In spectrum allocation, this model uses the definition of the lattice degree of nearness between fuzzy sets to calculate the difference between the actual comprehensive evaluation set and the ideal comprehensive evaluation set, and thereby quantifies the trustworthiness of non-malicious nodes and, combining with the multi-target optimization algorithm, determines the spectrum resources to be allocated to these nodes. This mechanism inhibits malicious behavior while encouraging cooperative behavior of nodes, thus achieving a joint design for spectrum sensing at the physical layer and spectrum allocation at the MAC layer. Simulation results and analysis show that the proposed model outperforms existing models in the system's sensing performance, throughput and fairness of spectrum allocation under malicious attacks.