面向车辆状态信息广播的功率控制算法

针对车载自组织网（VANET）中节点以固定功率发送信息导致的信道资源无法优化分配的问题，以车辆周期发送的状态信息的广播为研究对象，提出一种可自适应于车流密度变化的VANET功率控制算法。该算法通过定义功率控制周期构建并更新直接邻居列表，根据直接邻居车辆的位置来调整发射功率，进而控制节点的广播信息覆盖范围，实现信道资源的优化分配以及节点路由性能的优化。仿真结果验证了所提出算法的有效性，表明该算法能够有效根据车辆密度自适应调整发射功率、降低信道占用率并提高直接邻居数据包投递率，从而保证安全信息的有效传输。

Power control mechanism for vehicle status message in VANET

When the packets are broadcasted with the fixed power in Vehicular Ad-Hoc NETwork (VANET), the wireless channel may not be allocated reasonable. In order to solve this problem, a power control mechanism adapted to the variation of vehicle density was proposed. It is adaptive to the variation of vehicle density. The direct neighbor list of each node was constructed and updated in a power control period, the power that used to transmit the vehicle status message was adjusted according to the location of the direct neighbor to cover all the direct neighbors, thus wireless channel could be allocated more reasonable and the performance of router could also be optimized. The validity of the proposed mechanism was proved by the simulation results. It is also found that the proposed mechanism is useful for adjusting the transmission power according to the vehicular density, reducing channel busy ratio and enhancing the performance of packet delivery ratio among direct neighbors, which can ensure the effective transmission of the security information.