Research On Network Vertical Switching Algorithm In Vehicle Heterogeneous Network

At present,the vihicular network has become an important solution for the intelligent transportation system.The vihicular network can realize the goal of sharing information aomong the vehicles,the roads,the infrastructure and the intelligent mobile terminals,thus improving the road traffic Safety and efficiency.How to ensure seamless switching between heterogeneous networks is pretty valuable.This paper studies how to reduce the vertical switching delay and alleviate the ping-pong effect in the vehicular heterogeneous network environment composed of 3G,WLAN,Wimax and TD-LTE networks.The main work is as follows:(1)This paper firstly introduces 3G,WLAN,Wimax and TD-LTE networks respectively,and describes the network architecture and key technologies of the three networks respectively.The characteristics of the vihicular heterogeneous network are briefly described.The vertical switching process and classification are also depicted.(2)A network vertical switching algorithm based on optimal stopping theory is proposed for the vihicular heterogeneous network environment composed of WLAN network and 3G network.The algorithm integrates multiple performance indexes including cost cost,available bandwidth and data transmission delay.In addition,the algorithm can accurately predict the distribution of roadside base station(RSU)which follow the Poisson distribution model.The experimental results show that the switching strategy based on the optimal stopping theory is superior to the other two strategies and the classical cost function algorithm.(3)In order to extend the application scope of the algorithm,a vertical handoff optimization algorithm based on Markov process is proposed.This algorithm takes into account that the state transition of the available network can affect the quality of communication(QoS),which is different from other algorithms.Firstly,the Markov process is used to predict the state transition of the wireless network after decision-making.Then,the weight of the parameters is determined by fuzzy logic method.Finally,the optimal network is selected by comparing the total revenue of each network.The experimental results show that the algorithm can reduce the blocking rate and the average packet loss rate of the vehicle terminal(VT),and also ensure high load balancing and reduce the ping-pong effect.