中文摘要：

水声通信网介质访问控制（Media access control,MAC）协议决定了节点共享水声信道资源的方式,它直接影响到水声信道的利用率和网络的整体性能。本文简要介绍了Aloha、MACA-U和UW-CSMA/CA三种竞争式MAC协议的基本原理,并基于NS2仿真平台,在集中式单跳网络和分布式多跳网络两种拓扑结构中对Aloha、MACA-U和UW-CS/MACA三种竞争式MAC协议的吞吐量、平均端对端时延、冲突率和协议开销等性能进行对比,并分析数据包长度对三种协议性能的影响,为实用MAC协议的设计提供了有效的参考数据和策略。

英文摘要：

Media access control （MAC） protocol in underwater acoustic networks decides the way that nodes share the underwater acoustic channel＇s resource. It affects the utilization ratio of the underwater acoustic channel. In this paper, the basic principle of three contention-based MAC protocols namely additive link online hawaii system （Aloha） , multiple access collision avoidance for underwater （ MACA-U ） , and carrier sense multiple access with collision detection-based MAC protocol for underwater （UW-CSMA/CA） was briefly introduced. The throughput, the collision ratio, the average delay and the protocol expense of three contentionbased MAC protocols was simulated in both centralized single-hop network and distributed multi-hop network based on NS2. The performance of three MAC protocols affected by data packet size was also analyzed. The simulation results provide effective reference data and strategy for practical design of MAC protocols.