Research On Multiple Vehicles Data Dissemination Using Network Coding In Vehicular Ad Hoc Networks

In addition to solve vehicle traffic safety, recent development and standardization invehicular ad hoc networks have motivated increasing interest in data service for in-vehicleconsumption. In current intelligent transportation system, services are provided to vehicles usingexisting wide-area cellular infrastructure (2G/3G) or the roadside infrastructure based onDedicated Short Range Communication (DSRC) links proposed for VANET networks. However,both of these approaches have their own challenges: the modest data rate of present3G links inthe high-speed state and its high cost of data downloading on one hand, on the other hand limitedby the coverage of roadside access points and the number of access points arranged in the initialstages, leading to network connection is always intermittent which does not ensure a high-qualitynetwork connection. In order to solve the above popular content distribution (large multimediafiles for business service that are often commonly interested by most of the vehicles) difficulties,Vehicular Cooperative Downloading method arises.First, this paper improves vehicular cooperative downloading model by using the networkcoding method into data distribution process. The vehicles of geographical proximity form acluster of vehicles and download cooperatively. The use of wide coverage of mobile2G/3Gnetwork as a control channel and high data download rates of V2I communication via roadsideaccess points, increases the average download speed of vehicles and reduces the download time.Then, this paper mainly focuses on data dissemination in V2I stage. Compared with thetraditional random-based and feedback-based scheme, network coding aided scheme reduces dataduplication and does not need to upload directory information of received packets.Finally, these three methods are carried out mathematical derivation, calculated the averagetime needed to complete the download of whole file. Mathematical analysis and simulation resultsillustrate the efficiency of NC-based data distribution method and a low network overhead.