Research On Multi-hop Broadcast Technology Based On Traffic Flow Densityand Probability In VANET

With the development of Vehicular Ad-hoc Network,people have put forward higher requirements for transportation applications.The traditional communication protocol in Vehicular Ad-hoc Network is the wireless access(Wireless Access in Vehicular Environment,WAVE)protocol stack,because there is no data forwarding function.Can no longer fully meet the actual needs of the increasingly complex traffic environment for the application of Vehicular Ad-hoc Network.Based on the requirements of the actual traffic environment,this thesis designs and implements a Probability-based Adaptive Multi-hop Broadcast(PAMB)algorithm for complex car networking environments based on the standard WAVE protocol stack.At first,during the design and implementation of the PAMB algorithm,the characteristics of the standard WAVE protocol stack and the various problems and deficiencies of the existing similar algorithms are fully considered,and the deficiencies of the existing algorithms can be improve while ensuring compatibility Place.The core idea of the PAMB algorithm is that the node uses the data interaction with its neighbor nodes and the data relationship with the previous hop forward node dynamically adjust the weight of the forwarding probability,thereby dynamically changing the size of the forwarding probability and achieving dynamic adaptation to the network.The purpose of the environment.Secondly,the PAMB algorithm is composed of multiple sub-modules,namely information maintenance module,data interaction module,back-off waiting module,weight adjustment module,forwarding probability calculation module and forwarding decision module.Among them,the information maintenance module is mainly responsible for data storage and maintenance in the process of multi-hop broadcast protocol.The data interaction module is used to information exchange between neighbor nodes.The back-off waiting module is used for reduce unnecessary information conflicts.The weight adjustment module is responsible for dynamically adjusting the weights of different factors during the calculation of the forwarding probability.The module that calculates probability of forwarding and the forwarding decision module are jointly responsible for calculating the final forwarding probability and determining whether the data packet should be forward or not.Each module cooperates with each other complete with the task of multi-hop forwarding of specific data packets.Finally,this thesis designs and implements an adaptive multi-hop broadcast system based on the PAMB algorithm,and proposes a PAMB multi-hop broadcast system implementation that can ensure compatibility with the standard WAVE protocol stack.The experiment environment of PAMB algorithm is constructed using NS-3 network simulation tool,and compared with similar algorithms.The experimental results show that PAMB algorithm has certain advantages over similar algorithms in transmission delay,network load and reliability.A comprehensive theoretical analysis and simulation test are carried out on the performance of the PAMB algorithm,which proves that the PAMB algorithm can effectively improve the existing shortcomings of the multi-hop broadcast algorithm.