异构无线网络中基于模糊逻辑的分级垂直切换算法

在异构无线网络中，针对综合考虑网络端和用户端参数的垂直切换算法，参数权重难以确定，同时基于模糊逻辑的垂直切换算法存在复杂度高的问题，该文提出一种基于模糊逻辑的分级垂直切换算法。首先，将接收信号强度(RSS)、带宽、时延输入到1级模糊逻辑系统，结合规则自适应匹配，推理出QoS模糊值，并通过QoS模糊值对网络进行初步筛选得到候选网络集；然后通过触发机制触发2级模糊逻辑系统，并将候选网络的QoS模糊值、网络负载率、用户接入费用输入2级模糊逻辑系统，同时结合规则自适应匹配，得到输出判决值，从而选择最佳接入网络。最后，实验结果表明，该算法能保证网络性能的同时，降低系统的时间开销。

A Hierarchical Vertical Handover Algorithm Based on Fuzzy Logic in Heterogeneous Wireless Networks

In the heterogeneous wireless networks, the parameter weight is difficult to determine for the vertical handover algorithm considering the parameters of the network and the user, at the same time, the vertical handover algorithm based on fuzzy logic has high complexity. Considering this problem, a hierarchical vertical handover algorithm based on fuzzy logic is proposed. Firstly, the Received Signal Strength (RSS), bandwidth and delay are input into the first-level fuzzy logic system. Combining with the rule adaptive matching, the QoS fuzzy value is inferred, and the network is initially filtered by the QoS fuzzy value to obtain the candidate network set; Then, the second-level fuzzy logic system is triggered by the trigger mechanism, and the QoS fuzzy value, network load rate and user access cost of the candidate network are input into the second-level fuzzy logic system. At the same time, the output decision value is obtained by combining the adaptive rule matching, so as to select the best access network. Finally, the experimental results show that the algorithm can guarantee the network performance while reducing the time cost of the system.