车辆异构网络中预测垂直切换算法

在车辆异构网络中，针对垂直切换决策时刻之后网络状态的动态变化，提高切换性能问题，提出一种基于马尔可夫过程的预测垂直切换(M-VHO)算法。算法考虑了切换决策后网络状态的动态变化对车辆终端服务质量(QoS)的影响。其基本思路是:在需要垂直切换时，利用马尔可夫过程的转移概率预测未来网络状态的变化；另外，采用模糊逻辑方法确定评价属性参数权重；最后，比较切换决策、切换执行和切换之后时刻的总收益来优化选择最佳切换网络。仿真结果证明，该算法在确保较高负载均衡的情况下，可有效改进车辆终端的平均阻塞率及丢包率，降低乒乓效应，确保了车辆终端的QoS。

Prediction Vertical Handoff Algorithm in Vehicle Heterogeneous Network

A prediction Vertical HandOff (M-VHO) algorithm is proposed by using a Markov process in vehicle heterogeneous network, to improve handoff performance when network status dynamic transformation after the handoff decision. It takes into account influence of network status dynamic transformation on vehicle terminals Quality of Service (QoS) after the handoff decision. Its basic idea is in that a future wireless networks status transformation is predicted by transition probability of Markov process if vertical handoff is required; otherwise, the weight of evaluating attribute parameters be determined by fuzzy logic method; finally, the total incomes of each wireless network are compare, including handoff decision incomes, handoff execution incomes and communication service incomes after handoff execution, and the optimal network is selected. The simulation results show that when the high load balanced situation is ensured the algorithm effectively improves the average blocking rate and packet loss rate of vehicle terminal, reduces the ping-pong effect, and insure the QoS of vehicle terminal.