【作者】 吴云；

【导师】 韦岗； 熊尚坤；

【作者基本信息】 华南理工大学 ， 电子与通信工程， 2011， 硕士

【摘要】 随着水声通信技术研究深入,水声传感器网络在海洋环境监测、矿物资源开发、辅助导航、自然灾情预防、战略指挥等方面都有了广泛的应用。相比成熟的陆地无线通信,水声传感器网络存在可用带宽窄、传播时延长、信号衰减大等特点。因此,陆地无线通信MAC协议不能直接适用于水声通信,需专门研究适用于水声网络的专属MAC协议。通过参考大量国内外文献,本论文认为水声网络中主要需要解决几个问题:延时、能耗、公平性及可扩展性。传统的基于多次握手机制的MAC协议只会进一步加大水声通信延时,降低网络的吞吐量;而无序发送引发的数据包频率碰撞,严重浪费了节点的能量;延时导致的公平性失衡等现象也严重影响着网络的整体性能;新节点的加入或者旧节点的失效需要网络具备良好的可扩展性。针对多到一的监测型水声传感器网络,本论文结合水声信道的特点设计了一种基于TDMA的水声传感器网络MAC协议(UN-TD)。其基本设计思想是:汇聚节点基于动态感知到的监测节点到它的时延信息,集中调度各个监测节点的数据发送时隙、侦听时隙以及睡眠时隙,从而实现在无数据碰撞前提下,最大化网络整体吞吐量和能量利用效率。在NS2平台下,基于吞吐量、能量效率、平均时延、公平性这四个网络性能指标,本文将UN-TD与ALOHA协议、DACAP协议进行了仿真对比。仿真结果表明:在牺牲一定时延性能的代价下,UN-TD能够最大化水声信道的利用效率以及能量利用效率,适用于对时延不敏感的多至一的监测型的单跳水声传感器网络。更多还原

【Abstract】 With the fast development of underwater acoustic communication techniques, underwater acoustic sensor network (UAN) is being more and more used in the marine environment monitoring, development of mineral resources, navigation aid, natural disaster prevention, strategic command, and other aspects of the wide range of applications. Compared to the mature terrestrial radio communications, underwater acoustic sensor network has distinct characteristics, such as narrow available bandwidth, long propagation delay, and strong signal attenuation. Therefore, MAC protocols originated from the terrestrial wireless communication can not be directly applied to underwater acoustic communication, and dedicated MAC protocols should be proposed.By reviewing a large number of domestic and foreign researches under UAN, we identify several key problems that need to be addressed for designing MAC of UAN: delay, power consumption and fairness. Traditional handshake mechanism will worsen the acoustic communication delays and decrease the network throughput; unordered data transmissions lead to collisions and serious waste of energy; delay-induced unfairness impairs the overall network performance; the network is required to extendible enough to handle frequent entrance of new node or expiration of old nodes.Regarding to the special characteristics of underwater acoustic channel, we propose a dedicated Underwater TDMA MAC protocol (UN-TD) for the many-to-one underwater monitoring sensor network. Its basic idea is that, by dynamically monitoring the delay from the node to itself, the gate node or AP node schedules the sending slot, sleeping slot and listening slot for each client node in a centralized way, so as to maximize the overall network throughput and energy efficiency in the premise of guaranteeing collision-free packet transmission.We also compare UN-TD’s performance of throughput, energy efficiency, average delay, fairness against ALOHA and DACAP. Simulation results show that: UN-TD outperforms the other three protocols in throughput, energy efficiency and fairness, at the expense of inducing longer delay. It is suitable for delay-insensitive many-to-one underwater monitoring sensor network.更多还原