媒体访问控制（MAC）协议是水声组网最基础、最关键的核心模块。水声环境的独特性使实现稳定可靠、高效节能的MAC协议具有很大挑战，阻碍了其研究和应用的发展。围绕真实环境中由于水声Modem设计引起的实际问题及水声通信传统问题对MAC性能的影响，本项目拟按以下三个步骤对水声网络实用型MAC的设计、建模与性能评估进行深入研究：（1）针对“忙终端”问题提出基于随机接入的MAC协议成功传输概率模型框架，准确表征其碰撞行为并建立准确的吞吐量模型，为优化MAC设计和性能评估提供依据。（2）针对长前导码和低可用传输速率问题提出基于竞争的水声MAC协议冲突概率模型，深入分析其影响MAC性能的根本原因，为实用型MAC设计提供理论指导。（3）针对上述实际问题并充分考虑时空不确定性，提出基于分布式按需调度的无竞争实用型MAC协议算法，不依赖于全局信息，并根据节点的动态传输请求按需调动，具有很高的实用型及高效性。

The Media Access Control (MAC) protocol is the most basic and critical core module of the underwater acoustic network. The uniqueness of the underwater acoustic environment makes it challenging to achieve a stable, reliable, energy-efficient MAC protocol, hindering the development of its research and applications. Focusing on the actual problems caused by the design of the underwater acoustic Modem in the real operating environment and the impact of the traditional problems of underwater acoustic communication on the performance of the MAC protocol, this project intends to model and design the practical MAC protocol of the underwater acoustic network according to the following three steps: (1) A random based MAC protocol successful transmission probability model framework is proposed for the "busy terminal" problem, which accurately characterizes the collision behavior of random MAC and establishes an accurate node throughput model to optimize the MAC， provide the basis of MAC protocol design and performance evaluation (2) Propose the collision probability model of the competition-based underwater acoustic MAC protocol considering the long preamble and low available transmission rate, and deeply analyze the root causes of affecting MAC performance, and provide theoretical guidance for practical protocol design. (3) Aiming at the above practical problems and considering the uncertainty of time and space, a non-competitive practical underwater acoustic MAC protocol algorithm based on distributed on-demand scheduling is proposed, which does not depend on global information and is mobilized according to the dynamic transmission request of the node, which will be a very practical MAC protocol.