Aloha-LPD:一种用于水声通信网的MAC协议

Aloha-LPD:a MAC protocol for underwater acoustic networks

为了减小长传播延迟对水声通信网性能的影响,在传统Aloha协议的基础上,借鉴CSMA协议载波侦听的思想,提出了一种用于水声通信网的MAC协议Aloha-LPD.利用水声通信的长传播延迟,采用半双工的通信方式,增加节点等待ACK回复帧过程中接收数据帧的机制,使一个节点同时与多个节点无冲突地通信.通过OPNET建立仿真模型,分析结果表明,与传统Aloha协议和基于RTS/CTS握手的协议相比,Aloha-LPD协议能够提高网络吞吐量,减小网络的端到端延迟.水声传输信道的长延迟是水声通信网性能的一大瓶颈,但如果能合理利用,也能改善水声通信网的性能.

In order to minimize the impact of long propagation delay on the performance of underwater acoustic network,a MAC（medium access control） protocol suitable for an underwater acoustic network is proposed,which is called Aloha-LPD（Aloha with long propagation delay）.It was based on pure Aloha and carrier sensing in CSMA（carrier sense multiple access）.Aloha-LPD can make one node communicate with several nodes without collision by utilizing long propagation delay,half-duplex communication and mechanism of receiving data frame in the process of waiting for ACK（acknowledgement） frame.OPNET simulation was used to validate the protocol.Simulation results show that Aloha-LPD protocol can achieve higher throughput and less end-to-end delay than the pure Aloha protocol and RTS/CTS（request to send/clear to send） based protocols.Long propagation delay is the bottleneck for network＇s performance,but it can also be utilized reasonably to improved the network performance.