Research On The Network Selection And Handover Algorithm In Vehicular Heterogeneous Networks Based On VANET And LTE

Vehicular heterogeneous networks technology has become the inevitable trend with the development of vehicle network. Integration and application of various wireless communication technologies to the vehicular environment prove to be an effective way to enjoy multimedia resources and vehicle services on internet without the limitation of place and timewhen driving. Meanwhile, traffic safety and efficiency are ensured to improve human’s livelihood. Many efforts have been made to utilize the performance of the capability of network switching algorithm which is seen as the core technology concerning the research of the network handover technology in heterogeneous network. Currently, Vehicular ad-hoc network technology(VANET) has attracted extensive attention as an access standard for communication. Undoubtedly, LTE has been viewed as the key technology of the fourth-generation mobile communication system, which can be well applied to the vehicular networking.Therefore, this paper focused on selection and handover technology of vehicular heterogeneous network based on VANET and LTE.To begin with, on object to the problem of load imbalance caused by uneven and random vehicle distributionin heterogeneous vehicle networking, a Load Balancing Based Network Selection method(LBNS) was proposed to access the appropriate network for initial vehicles. Relatively low demand of data transmission and bandwidth for initial vehicle made it possible to consider the condition about the usage of physical resources as the load for LTE network and the situation concerning the usage of channel status as the load for VANET.The load balancing method was adopted to select and evaluate the network for purpose of achieving the maximize load balance index as network access. The kinematic property of vehicle nodes was taken into account during the VANET optimal channel evaluation. Vehicle nodes with similar motion properties was preferred to join the same VANET channel to an extreme in order to maintain the stability of the VANET communication link.Then, Residence Time Based Network Handover Algorithm(RTNH) was proposed to solve the problem of frequent network handover caused by fast and dynamic change speed of vehicle in heterogeneous vehicle networking. Firstly,RTNH predicted the movement of vehicles to estimate its resident time in the coverage of the current LTE base station, and thendividedvehicle nodes into narrow or wide mobile according to the value of resident time. For narrow mobile vehicles, a more stable performance of LTE network had been obtained. Moreover, the LBNS method was used as thehandover strategybetween this LTE network and VANET. However, for wide mobile vehicles, frequent entrance and out of the coverageof multiple LTE base stations was detected. Obviously, a method of multi attributes decision with prioritywas essential when addressing thehandover strategybetween multi LTE networks and VANET.Finally, a contrast analysis between RTNH methods and the other three methods based on Received Signal Strength method,traditional MADM method and based on Bayesian Decision Theory method was made through SUMO and NS-3 simulation software. Even if the vehicle was in different quantity or at various vehicle speed in simulation, RTHNmethod exhibited better network performance along with fewer handover times thus contributing to the improvement in the stability and efficiency of the network handoverinvehicular heterogeneous networks.