Design Of Routing And Switching Algorithm For Multi - Interface Wireless Ad Hoc Networks

VANET (Vehicular Ad Hoc Network) is the important foundation for intelligent transportation, which constitutes an autonomous system between vehicles based on wireless communication technology and owns the wide foreground about safety driving and traffic congested relieving. Routing protocol is a hot topic in the field. The development of mobile terminal design and routing protocols correspond to each other, which has a variety of practical significance to vehicle ad-hoc network.By analyzing the characteristics of the existing routing protocols and summarizing routing protocols for the vehicle-vehicle (V2V) communication modes in VANET and adding multiple radio interfaces to the mobile terminal idea, the thesis proposes the Multi-Interface Routing and Interface-Switch algorithm, which is in the background of frequently changing topology and lacking forwarding node at forwarding path. The algorithm solves the above two problems by updating real-time neighbor table information that gets from periodically broadcast, and calculating multi-interface path. The source node will traverse neighbor list to find the one hop node to the destination node, when the communication between network nodes starts. If the destination node is not in the neighbor list, the source node will initiate a broadcast. The algorithm choses the RF interface on the basis of Restricted Rorwarding Algorithm when it performes one hop transmission. Restricted Rorwarding Algorithm includes three important factors, such as network load, information of RF interface and last interfaces used to communicate.In order to verify the correctness and effectiveness of the algorithm, this paper implements an embedded vehicle wireless communications platform and achieves a wireless ad hoc networks multi-interface switching algorithm on this platform. The platform achieves channel access control algorithm by useing FPGA’s flexible and fast control characteristics and extends two different frequencies RF interfaces which is coordinated by the control module through SPI interface to switch freemly. The uClinux can control the complex network layer logic better through the driver module, which is responsible for interaction between the upper application and the underlying hardware. The platform combines embedded system with FPGA to achieve the purpose of flexible and efficient control, simple and unified interface.By actual test platform, setting a scene with a certain range nodes, the algorithm was preliminaryly verified the correctness and effectiveness. Experimental results show that the Multi-Interface Routing and Interface-Switch algorithm can effectively reduce the switching latency between end to end and improve network resource utilization.