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Research On SIC-based MAC Protocol For V2I Communication In Internet Of Vehicles

Posted on:2021-02-20Degree:MasterType:Thesis
Country:ChinaCandidate:H C ZhengFull Text:PDF
GTID:2492306047487764Subject:Communication and Information System
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Vehicular Ad Hoc Network(VANET),as an important part of Intelligent Transportation Systems(ITS),has a significant potential to enable new applications in the vehicular domain,some of which improving traffic safety,updating traffic information and reducing environment pollution.V2 I communication allows vehicles to establish communication links between driving and infrastructure and provide relevant entertainment services for drivers.Therefore,V2 I communication has become a key research field of ITS.MAC protocol determines the communication resource allocation method,which plays an important role in communication nodes’ efficient access to channel,the reasonable allocation of communication resources and guaranteeing Quality of Service(Qo S).This thesis starts from improving the channel utilization while guaranteeing the real-time and reliable communication among vehicle nodes in V2 I communication scenario.Through a large amount of literature investigations,it is found that as the density of vehicle nodes increases,more and more packets need to be retransmitted due to the packet collision,which leads to a higher packet loss ratio and access delay.The existing MAC protocol adopts carrier sense and back-off mechanisms to avoid collisions in the network.When collision happens in the process of packet transmission,the collided packet will be immediately discarded.Therefore,this thesis uses successive interference cancellation technology to recover collided packets and realize multi-packet reception,then proposes a novel MAC protocol based on successive interference cancellation.The proposed protocol first uses the packet repeat policy at the transmitter,and then combines the inter-slot interference cancellation and intra-slot interference cancellation to recover collided packets.Further,this thesis uses the network simulator OMNe T++ to simulate the designed MAC protocol for V2 I communication scenario.Simulation results show that the proposed MAC protocol effectively improves the channel utilization while ensuring high reliability and low access delay in the case of a fixed frame length.Then,in response to uncertain network load caused by vehicle nodes density changing,an adaptive adjustment protocol based on successive interference cancellation is further proposed.Aiming at dynamic changes of system load,an adaptive frame length adjustment algorithm is proposed at the receiver which the frame length is dynamically adjusted according to the load status,at the same time,Q-learning algorithm is adopted by sending nodes to obtain the optimal access slot selection in order to achieve balanced load,and further improve network performance.The adaptive adjustment protocol effectively improves the flexibility and scalability of the network.By reducing the frame length under low-density nodes,unnecessary waste of resources can be avoided.Meanwhile,the receiver increases the frame length appropriately under high-density nodes to achieve efficient and reliable data transmission.
Keywords/Search Tags:Vehicular Ad Hoc Network, V2I communication, MAC, Successive Interference Cancellation, Adaptive adjustment, Q-learning algorithm
PDF Full Text Request
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