Design And Performance Analysis Of Multichannel MAC Scheme With RSU Coordinated For The Internet Of Vehicles

With the development of mobile communication,Internet of Vehicles(IoVs)plays an important role in the future Intelligent Transportation System(ITS).There are two types of messages in the IoV: safety messages for guaranteeing the safety of vehicles which owns higher priority,and service messages which is designed to provide drivers and passengers with service information sush as online maps.Wireless Access in Vehicular Environments(WAVE)is a set of protocol designed for transmitting different messages in the IoV.The standard of IEEE 802.11 p and IEEE 1609.4 are two important protocols which are designed for the WAVE Media Access Control(MAC)layer.First of all,in this thesis,an RSU coordinated multichannel MAC scheme is proposed for IoV based on the standard of IEEE 802.11 p and IEEE 1609.4.For safety messages transmission,in order to avoid the collision between multiple nodes,the broadcasting order can be determined by RSU based on the updated vehicular list.Furthermore,an authentication process based on dynamic frame-slotted ALOHA algorithm with access control factor is proposed to identify the vehicular list within a certain period.For service messages transmission,an improved service channel reservation mechanism is designed to transmit service messages in the proposed scheme.Different from the existing coordinated multichannel MAC(C-MAC)scheme,the idle service channel at the reservation time can be used to transmit service messages.With such mechanism,the utilization of service channels can be improved.Both theoretical and simulation results show that the proposed scheme can achieve better successful certification rate,higher throughput of service channel and lower delay of service messages transmission compared to the C-MAC scheme.In addition,an optimized scheme for dynamically adjusting the parameters of multichannel MAC Scheme based on the traffic flow is proposed in this thesis.The traffic data obtained by the ITS system and IoVs can be used to dynamically adjust the parameters of the proposed RSU coordinated multichannel MAC scheme.The flexibility of the RSU coordinated multichannel MAC scheme can be improved while the performance of safety messages and service messages transmission can be guaranteed by adopting this optimized scheme.Simulation results obtained by using actual road traffic flow data show that the optimized scheme can dynamically adjust the parameters of RSU coordinated multichannel MAC scheme based on the trend of traffic flow,and achieve low delay of service messages transmission while the reliability of safety messages is guaranteed at the same time.