一种低碰撞多传输的水声无线网络MAC协议

针对水声通信网络中长传播时延带来的时空不确定性以及现有水声MAC协议中存在信道预约阶段握手碰撞概率较高的问题，提出了一种碰撞避免并发传输的MAC协议(Collision Avoidance Concurrent Transmission MAC protocol，CACT-MAC)。CACT-MAC协议先由目的节点发起广播测试帧，对信道进行预约。收到该测试帧的源节点通过发出带有并发传输条件的控制包进行并发传输节点的获取，同时这个控制消息还能够为后续数据包的追加传输提供支持。此协议包含一种发送优先级确定机制：根据源、目的节点传播时延与中继数据包数目来确定发送顺序。与DCT-MAC协议和Slotted-FAMA协议相比，所提协议在网络吞吐量上分别提高了5.49%和9.98%，同时在信息控制开销方面分别降低了18.87%和20.56%。

A Low Collision Multi-transmission MAC Protocol for Underwater Acoustic Wireless Networks

For the time-space uncertainty brought by the long propagation delay in underwater acoustic communication network and the high probability of handshake collision in the channel reservation stage in the existing underwater acoustic MAC protocols,a collision avoidance concurrent transmission MAC protocol(CACT-MAC) is proposed.In the CACT-MAC protocol,the destination node first broadcasts a test frame to reserve the channel.The source node that receives the test frame obtains the concurrent transmission node by issuing a control packet with concurrent transmission conditions.This control message can also provide support for the addition of subsequent data packets.Additionally,this protocol includes a sending priority determination mechanism:the transmission order is determined by the number of relay packets,the propagation delay between source and destination node.Compared with the Data Concurrent Transmission MAC(DCT-MAC) protocol and the Slotted Floor Acquisition Multiple Access(Slotted-FAMA) protocol,the proposed protocol increases the network throughput by 5.49% and 9.98%,and reduces the information control overhead by 18.87% and 20.56%,respectively.