车联网VANETs中一种分发紧急消息的广播方案

A new broadcasting emergency message algorithm in VANETs

车载网VANETs中的车间通信V2V能够实现车间紧急消息的传递。然而,传统的广播算法采用RTB和CTB握手机制,同时在传递消息后,还需确认ACK环节,降低了紧急消息传递速度、增加了传输时延。为此,提出了一种广播紧急消息的新型算法。该算法利用数据包的信噪比SNR和节点位置坐标信息计算最大竞争窗口,再在最大竞争窗口内随机选择一个时隙用于转发紧急消息,避免了RTB/CTB握手机制。当源节点收到重播的紧急消息,表明紧急消息已成功传到下一节点,将其作为抑制源节点再广播紧急消息指标,避免了ACK确认环节,从而提高了紧急消息的传播效率和速度,降低了传输时延。

In Vehicle Ad hoc Networks ,Vehicle-to-Vehicle communication is able to transmit emergency message. However, traditional broadcasting algorithm introduces the Request to Broadcast and clear to Broadcast handshake mechanism. Meantime, after broadcasting message, it need acknowledge process, which reduces the transmission speed of emergency message, increase the transmission delay. Therefore, a new broadcasting emergency message algorithm is proposed. It uses Signal-to-Noise Ratio and location information to compute the contention window sizes, and randomly choose a time slot from the contention window sizes to transmit the emergency message. It avoids the RTB/CTB handshake mechanism. When the source node received the rebroadcasted emergency message, it means that emergency message has been successfully transmit, which inhibition of source node to broadcast an urgent message indicators, and avoid the ACK, so as to improve the transmission efficiency and speed, reduce the transmission delay.