Research Of The Multiple Attribute Vertical Handoff Based On Vehicular Heterogeneous Networks

Car applications and services demand are growing with the increase number of cars.Vehicles can communicate with each other as well as the Road Side Units(RSU)to get the information such as road traffic condition,safety warning,path information and so on.However,there is no network can cover everywhere and provide ubiquitous overall service.Therefore,vehicular heterogeneous network which integrates a variaty of wireless access technology has become an effective way to solve this problem.Vertical handoff is the key technology in the vehicular heterogeneous network to get seamless services and its core is to choose the network accurately and independently.This research focuses on the implementation of the vertical handoff in a more accurate way and using the technologies of the vehicular heterogeneous network.The contents of this research include the following several parts:Firstly,we describe the multi-protocol attribute selection method.Then the multi-service weight determination method is presented based on the data flow,video streaming and voice service.Secondly,a detailed analysis of the vertical handoff algorithms is given,including Single Criteria Algorithm(SCA),Cost Function Algorithm(CFA),Multiple Attribute Additive Weighting(MAW)and Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)based on Multiple Attribute Decision Making Algorithm(MADM).Through the function modules building,the units deployment and communication mode setting,the heterogeneous simulation platform is built on VanetMobiSim and NS3.Then we discuss the differences of above several algorithms.The results show that using multiple attribute and multi-service weight can make the average packet transmission delay and packet loss rate lower.The MADM has a better performance than CFA and SCA.The average packet transmission delay and packet loss rate have been reduced by 19 ms,9% on CFA compared to SCA,and 6ms,4% on MADM compared to CFA.Finally,the article puts forward new algorithms on the switching trigger process and network choosing process according to the disadvantages of the MADM algorithm.For the switching trigger process,a new model is raised based on the network priority.For the network choosing process,a hybrid weight calculation method is presented based on the attribute standard deviation characteristics.In the simulation platform,the improved methods are analyzed and compared based on the MAW and TOPSIS algorithms.The average packet transmission delay and packet loss rate are significantly lower and the switching performance and communication quality are improved.