摘要： 传统认知车载网(CR-VANET)中采用基于竞争的介质访问控制(MAC)协议,该协议在高车辆节点密度情况下会导致较高的数据包碰撞率,严重影响安全消息传输的时延和可靠性。针对该问题,提出一种基于路段划分的协作MAC协议,以优化CR-VANET系统性能。通过对每段道路的簇首进行时隙分配,减少数据包的碰撞概率,降低传输时延。同时为确保消息传输的有效性和可靠性,在空闲时隙选择辅助节点给接收数据失败的节点重传消息。性能分析和实验结果证明,该协议能够有效降低丢包率和传输时延,提高网络的吞吐量。

关键词: 认知无线电, 车载自组网, 介质访问控制, 安全消息, 辅助节点

Abstract: Traditional Cognitive Radio-Vehicular Ad-hoc Network(CR-VANET) employs the contention-based Medium Access Control(MAC) protocol.This MAC protocol may lead to high packet collision under high-density of vehicular nodes situation,which makes the transmission delay and affects the reliability of safety messages.To optimize the system performance of CR-VANET,a cooperative MAC protocol based on road segmentation is proposed.The packet collision probability and the transmission delay can be effectively reduced by allocating slots through Cluster Head(CH).Besides,in order to guarantee the validity and reliability of the message transmission,auxiliary nodes are selected in idle slots,which can help to retransmit the message to the node that fail to receive the data packet.Performance analysis and experimantal results show that this protocol can efficiently decrease the packet drop rate and transmission delay,meanwhile improving the network throughput.

Key words: Cognitive Radio(CR), Vehicular Ad-hoc Network(VANET), Medium Access Control(MAC), safety message, auxiliary node

中图分类号: 

• TP393