Vehicle Wireless Self-organizing Network MAC Protocol And Simulation Studies

Vehicle wireless ad-hoc network(VANET) can provide people with safe, comfortable, and convenient transportation. International Organization for Standardization IEEE established the IEEE 802.11 p and IEEE 1609 working group co-specification vehicle network research process to develop a protocol standard VANET. In the IEEE 1609.4 standard, the channel is divided into a control channel and service channel, the former security for the transmission of information and control information, while the latter is used to transmit secure information unrelated to business information.IEEE 1609.4 standard vehicle network MAC layer using multi-channel transmission mechanism, SCH slot with six traffic channel, 1609.4 agreement does not specifically assign these measures clearly defined channels. In order to improve the transmission performance of business information, this paper studies the allocation strategy MAC layer multiple channels and time for vehicle network V2 I interactive mode, a new resource allocation algorithm based on the relative position of nodes and business types. Upon receiving the roadside service facilities demand node can be calculated according to the position information and the Qos of the current service priority level of each node in the node, then when the treatment of the corresponding business requirements necessary to calculate the evaluation function value of the different allocation methods, to choose the less need slot, channel switching times, and less able to keep each channel load more balanced approach. In order to ensure reliable, real-time delivery of safety information provided, greatly enhance the transmission performance of the traffic channel.In a large vehicle traffic density environments, the limited bandwidth resources may not meet the business needs of the node. This paper presents an in-vehicle network admission control and channel reservation policy, because the vehicle on the road with a running one-dimensional vehicle easier to master node. RSU resource reservation mechanism for forecasting results more meaningful, reserve resources will be more accurate. Further, considering the running speed of the vehicle is much greater than the node running speed of the mobile terminal, and the speed and direction of the vehicle at any time to change in order to improve the accuracy of channel reservation, RSU will change according to the traffic density and dynamic updates for to node position information. In order to ensure that the existing services are not dropped as far as the admission of new users of the service.In order to influence resource allocation algorithm for on-board network performance validation to make paper on OPNET network simulation software to build a vehicle network MAC protocol simulation platform. And to verify the effect of the use of simulation platform based on the relative position of nodes and business type of resource allocation algorithm for reliability of business information transmission throughput, end to end delay and packet generation systems, and with the idle channel resource allocation algorithm based on simulation results of the analysis and to make comparisons.