中文摘要：

当目标区域距离广播源节点过远时,基于机会网络的车联网安全消息广播算法往往造成过高的传输时延,难以保证安全消息的QoS需求.广泛部署的蜂窝移动网络为安全消息广播提供了一种新思路.基于VANETcellular网络架构,该文提出了一种安全消息广播中继节点选择方法.通过一种改进的RTS/CTS交互,根据候选车辆的蜂窝网络信号强度及其增量、链路稳定度、信道质量、地理位置等参数选出最佳的广播中继节点,并通过该节点将安全消息传递给服务器,最终由服务器传递给目标区域.数值分析和实验仿真结果显示,该方法不过分依赖于车流密度,也不需要额外部署基础设施,同时能够快速、可靠地传递安全消息,减少车载网络中信息冗余,提高了网络资源利用率.

英文摘要：

The broadcast of safety message based on opportunistic network always lead to high latency when the target area is far from the source node.In this circumstance,the QoS of the safety message dissemination will have no insurance.The rapid popularity and development of cellular network provides a new method for the broadcast of safety message.Based on the VANET-cellular architecture,a selection method of safety message broadcast relay was proposed by us.We first introduce a relay metric for relay selection by jointly considering cellular signal strength and its variation,link stability,physical-layer channel conditions and geographical locations.Then,using the relay metric,a unique relay vehicle is selected to forward the safety message to server by cellular network.The server will send the safety message to the target area afterward.Simulations and mathematical analysis demonstrate that the proposed method can minimize the broadcast message redundancy,improve the network resource utilization,rapidly and reliably transmit the safety message.What＇s more,the encouraging results are not excessively dependent on the density of traffic and widely deployment of infrastructures.