When node density of vehicle Ad-hoc network (VANET)is high,the number of channel collisions increases occurrence of congestion in VANET. To solve this problem,a dynamic power control algorithm is proposed. The network condition of nodes is evaluated by the value of channel busy ratio (CBR ). In case of network congestion,the congestion information is flooded,so that other nodes can adjust transmission power accordingly. Moreover,a power control function is designed,in which power coverage and the number of covered nodes are considered. The simulation results show that this method can adaptively adjust the transmission power and performs well in reducing the probability of channel overload and improving the packet reception rate.%针对车载自组网中,节点密度较高时,容易出现网络拥堵的情况,提出了一种动态调整消息发射功率的方法.通过信道忙闲比例(CBR)评估节点的网络状况,并在出现网络拥堵时泛洪广播拥堵信息,通知其他节点作出相应的功率调整.综合考虑功率覆盖范围和覆盖节点数两方面因素,设计了功率调整曲线.实验结果表明:方法能根据网络状况自适应地调整发射功率,降低了发生信道过载的可能性,并提高了信标消息传递的成功率.
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