【作者】 丛艳平；

【导师】 魏志强；

【作者基本信息】 中国海洋大学 ， 地图学与地理信息系统， 2011， 博士

【摘要】 进入21世纪以来，随着世界经济和军事发展的需求，海洋资源开发、海洋能源利用等现代海洋高新技术的研究已成为世界新科技革命的主要领域之一，其中水下无线通信网络关键技术与装备已成为各海洋大国不遗余力进行研究的主要对象。水下无线通信网络设备的发展对于建立水下立体通信网络、水下无线预警网络、水下无线导航网络等系统具有重要意义。为满足当前海洋探测、海洋军事等领域对水下通信的要求，该通信网络在感知环境因素，自适应调整通信模式的基础上，既要能够提供远、中、近程中低速实时数据和语音通信，又要能够提供中、近程实时高速图像数据传输及多媒体通信功能。因此，为适应以上需求，本文研究了多模式自适应水下无线通信网所涉及的一些关键技术和内容。具体研究内容包括以下几个方面：（1）提出了基于软件无线电技术的多模式自适应水下无线通信网络的概念和相应的框架结构。并对其物理层、链路层和网络传输层所涉及的相关协议进行了简要分析。同时，针对水下无线通信网的安全需求，提出了水下无线通信网的安全体系结构框架，并进行了简要的分析。（2）介绍了水下无线光通信信道以及水下无线水声通信信道的特点和建模方法，研究了分别适应于深海信道的LDPC空时编码方案，以及适应于浅海信道的TURBO空时编码方案。为简化接收端解码的复杂度，研究了统一的自适应解码方案。（3）根据水下无线通信系统对调制解调方式的需求，通信节点首先根据数据量大小以及对速率和带宽的要求，确定调制模式。同时，结合MAC层协议，研究创建了一种跨层的自适应调制解调系统框架，利用收发双方的握手信息携带当前信道状态，由发射方根据马尔科夫模型预计信道未来状态，从而自适应选择合适的调制制式，并利用握手信号通知接收方。为满足水下通信对功率、频率等资源的特殊要求，发射方根据握手信息，判断双方通信距离，并依据距离与信道信噪比的关系，根据注水原则，确定最优资源分配方案。（4）成簇策略是水下通信网拓扑的核心算法，由于我们关注的重点在于如何更大限度的节省能量，提高整个网络的寿命，因此，我们将成员节点的剩余能量与整个簇的剩余能量的加权平均值的比值作为选取簇头的依据，提出了簇头选择算法。针对分簇的水下无线通信网络拓扑结构，为有效降低冲突发生的概率，避免隐藏端问题，我们研究了簇内节点之间的基于时隙分配的EQE-MAC协议，当节点需要与簇头节点进行数据交互时，只有在属于自己的通信时隙内才能进行通信，其余时间处于睡眠状态。由于簇间通信时，难以进行准确的时隙分配，以及时隙同步，因此，我们研究了预约（Reservation）-监听（Monitor）-睡眠（Sleep）方式，即RMS-MAC协议。同时，为保证重要数据的优先发送，我们研究了基于优先级的自适应访问控制工作方式来支持猝发通信模式。由于我们假定簇内为一跳网络，因此针对簇间存在移动节点的场景，我们提出了基于VBF的能量改进路由协议算法。整套网络协议都是从能量均衡和能量节省的角度出发，使得整个网络的节点能量分布更加平均，以便于延长整个网络的生命周期。（5）提出了以FPGA、DSP、以及ARM等可编程器件为主的基于软件无线电技术的水下无线通信节点构架。更多还原

【Abstract】 Since the21st century, with the needs of the development of the military and worldeconomy, the marine high-techs such as exploitation and utilization of marineresources hasbecome one of the major fields of the new science and technologyrevolution. Every maritime power around the world is accelerating the research on keytechnology and equipment of underwater wireless communication. The development ofunderwater wireless communication networkis significant to the establishment ofunderwater wireless early warning system and underwater wireless navigationsystem.According to the requirements of exploitation and utilization of marine, thecommunication system can detectenvironment factors, adaptively adjustcommunication scheme. What is more, the communication system can supply variousways of services: short, middleand long range low-speed real-time communication ofdata and audio, middle range high-speed real-time communication of multimedia andimage data. To meet demands above, this paper research onsome key issues ofmulti-mode adaptive underwater communications network.The detailed contents are as follows：(1) The concept and composition of Multi-mode Adaptive Underwatercommunications network based on software-defined radio is proposed. The physicallayer, link layer and network layer protocols are briefly analyzed. Meanwhile, to meetthe need of security, a security architecture is proposed and briefly analyzed.(2) The characteristic and modeling method of underwater wireless acoustic andoptical channel is proposed. A space-time codes project based on LDPC is proposedfor shallow water and a space-time codes project based on Turbo is proposed for deepwater. To simplify decoding complexity at receiver, a unified adaptive decodingscheme is proposed.(3) According to the need of modulation and demodulation, communication nodefirstly choosesthe type of modulation based on the data quantities and the demand ofbandwidth. Meanwhile, a cross-layer adaptive modulation and demodulationarchitecture combined with the MAC layer protocol,is introduced. The future state ofchannel is anticipated by sender using Markov model. And then the sender adaptivelychooses appropriate modulation scheme and notifies the receiverby handshaking signal.To satisfy the special requirement for resources (eg. power, frequency), the sendercalculatesthe communication distance based on handshaking signal. And then thesender determinesthe optimal resource allocation plan based on Water injectionprinciple and the relationship between distance and SNR. (4) The cluster formation strategy is the core algorithm of underwatercommunications network topology. In order to save energy of node and prolonglifetime of whole network, the cluster-head election algorithm based on the ratio ofresidual energy of nodes and residual energy weighted average of whole cluster isintroduced. A EQE-MAC protocol which is based on time slot is proposed to guaranteethe minimal opportunity of confliction and solve the hidden-end problem. The nodeis allowed to communicate with cluster-head only in the assigned time slot,andin othertime it is in sleep model. It is difficult to synchronize time slot, so aReservation-Monitor-Sleep MAC (RMS-MAC) protocol is studied in this paper.Inorder to guarantee important data can be transmited on time, we adopt adaptive accesscontrol scheme to offer burst communication. In our assumptions, nodes generate alarge number of one-hop clusters. Aiming at the sceneof mobile nodes between clusters,we propose an improved routing algorithm based on VBF. The aim of the wholeprotocol is to save energy and prolong the lifetime of entire network.(5) The platform of underwater wireless communication node which is based onprogrammable logic devices (FPGA,CPLD,ARM) are proposed in this paper.更多还原