| Actually, in the application of VANET, there are many network environment factors, including:network scale, mobility model, characteristics of application and other factors, which affect the communication performance of the network. This paper focuses on the three external environment factors:node velocity,node distance,network density. However, compared to MANET, the mobility model of VANET is more complicated. So, this paper proposes two scenes in high-density urban areas:the intersection scene which is most common and causes traffic accidents easily and the overpass scene which used to ease traffic pressure, in these two scenes mainly analyses communication performance of active routing protocol-OLSR and passive routing protocol-AODV.Based on the OMNeT++ network simulation platform, this paper studies the performance of routing protocols which affected by the three external environment factors, and makes a number of simulation experiments under two typical mobility models of high-density urban areas, the results indicate that mobility model is one of the most factors affecting communication performance of network. Through the deduction and analysis of network connectivity probability, it is consistent with the simulation results:decreasing the node distance and increasing the network density can improve the network connectivity; and decreasing the node velocity can improve the network connectivity effectively, this improvement can improve the communication performance of routing protocol. Comparing AODV with OLSR, we have some conclusion as follows:the routing protocol of AODV is more suitable for large-scale network. However, the adaptable of AODV is not strong in the two scenarios. So in different scenarios, we should choose route protocols according to the different needs of business. Optimum performance of route protocol does not represent strong adaptability to the external influence factors. |
PDF Full Text Request