Study of Underwater Wireless Multi-point Communication System

随着世界各国海洋开发和海洋军事领域的飞速发展,对水下传感网络、水下监视系统、水声预警网络的需求越来越迫切。这里讨论一种采用跳频通信方式,以凌阳16位单片机SPEC061A为控制核心,通过主节点向各分节点发送信息或指令,实现水下无线多点通信。分析了通信节点的硬件和软件设计。通过水池实验证明该系统能够可靠稳定的工作,具有良好的性能。Along with exploiture of the ocean resources all over the world,it is necessary to cry for research of underwater sensor network,underwater monitoring system and underwater acoustic prewarning system.A way of frequency-hopping communication using 16 b MCU SPEC061A as the control core,sending information or index to sub-node by main node,the underwater wireless multi-point communication is realized.The hardware and software design of communication node are analysed.It proves that the system is stable and reliable,with good performance through the experiment of pool.国家自然科学基金资助项目(60672046

基于Chirp-BOK扩频的水声通信系统

利用线性调频(Chirp)信号在水下通信中具有良好的抗噪声和抗多径特性,提出基于Chirp-BOK(binary orthogonal keying,二进制正交键控调制)扩频的水声通信系统。系统采用二进制正交键控调制以及匹配滤波接收器,利用正向调频信号和反向调频信号,结合BOK调制技术,实现适合水声环境的扩频通信系统。噪声信道和多径信道下的仿真实验结果表明,该系统具有良好的抗噪声和抗多径性能,适用于水声系统的扩频通信。国家自然科学基金项目(61701422);;福建省自然科学基金项目(2017J01785,2016J01323);;厦门理工学院高层次人才项目(YKJ15034R);;水声通信与海洋信息技术教育部重点实验室(厦门大学)开放课题基金(201602

Research on Localization and Tracking for Mobile Vehicles in Underwater Acoustic Sensor Networks Based on Factor Graph Theory

水声传感器网络一直是水声领域研究中倍受关注的热点，在海洋监测、海洋开发，海洋国防安全等方面都有广泛的应用。目标定位，特别是移动目标定位，是水声传感器网络应用不可或缺的一部分，具有重大应用价值。 相比传统的水下定位方法，基于水声传感器网络的定位技术可通过组网的传感器节点实现节点间的信息共享和融合，增加定位手段，提高定位精度和定位服务的覆盖范围，是当前水声定位领域研究的新热点。但是，由于水声环境的特殊性和复杂性，水声传感器网络具有移动性、稀疏性、能量受限、信道复杂等特点，对水下定位技术的发展提出了严重挑战。 本文围绕水声传感器网络的移动目标定位跟踪问题展开研究，针对传统水声传感器网络定位技术的...Underwater acoustic sensor networks (UASN) have aroused increasing interests in the realm of underwater acoustic research, because of its potential in a wide variety of civil and military applications, such as marine observation, oceanic exploration, maritime national defense and security, and so on. Positioning, especially for mobile underwater vehicles, is a crucial requirement in UASN and widel...学位：工学博士院系专业：信息科学与技术学院_通信与信息系统学号：2332009015336

Joint time synchronization and tracking for mobile underwater systems

Conference Name:8th ACM International Conference on Underwater Networks and Systems, WUWNet 2013. Conference Address: Kaohsiung, Taiwan. Time:November 11, 2013 - November 13, 2013.ACM SIGMOBILETime synchronization and localization are key requirements for distributed underwater systems consisting of numerous low-cost submersibles. In these systems, submersibles are highly resource constrained and typically have limited acoustic communication capability. We investigate the problem of time synchronization and tracking for submersibles that only have the capability to receive acoustic signals. Traditional Long Base Line (LBL) systems track the location of submersibles by providing a GPS-like infrastructure that consists of a few reference beacons at known locations. In these systems the unknown positions of submersibles are estimated from beacon transmissions using time-difference-of-arrival (TDoA) based localization. As such TDoA makes the key assumption that beacon transmissions occur nearly concurrently in time. While this assumption is ensured in small LBL deployments it does not hold as the size of the system scales up. In this paper we identify scenarios where signals from multiple beacons are significantly lagged in time. We further identify the motion of the submersible between signal arrivals as a key factor that deteriorates the performance of TDoA, when transmissions are not concurrent. To address this problem we propose to track the submersible while performing time-synchronization. Our proposed technique, called Time of Arrival based Tracked Synchronization (ToA-TS) essentially extends GPS like localization for scenarios where beacon transmissions are not concurrent and submersibles are not capable of two-way communication. Copyright 2013 ACM

The Simulation Study of the Cooperative Diversity Based on ofDM Modulation

协作分集在无线通信中应用极其广泛,正交频分复用技术(OfdM)鉴于自身优势,在系统的频谱利用率、功率利用率、系统复杂性等方面具有很强的竞争力.首先介绍了协作分集中的两种协作方式与OfdM系统框架,对比分析了解码转发与放大转发在实现各自转发上所具有的优缺点;对比分析了CrC编码OfdM系统与卷积码编码OfdM系统仿真性能,决定采用卷积码实现OfdM协作分集中解码转发法(dECOdE And fOrWArd,dAf)的编解码,并对OfdM协作分集的两种协作方式进行了系统仿真.仿真结果表明,加入协作分集的OfdM系统,获得了显著的分集增益,系统性能得到提高.Cooperative diversity is widely used in wireless communication.On the other hand,orthogonal frequency division multiplexing(ofDM) is highly competitive due to its advantages in systematic spectral efficiency,power utilization and the systematic complexity.In this paper,two methods to realize cooperative diversity in ofDM systems and the frame of the ofDM are proposed;compared the CRC coding ofDM system with the convolutional coding ofDM system,and analyzed the performance of the CRC coding ofDM system and convolutional coding ofDM system,we decide to adopt the convolutional codes to achieve the DAF of the cooperative diversity.Two cooperative protocols in ofDM cooperative diversity system are simulated.As is showed in the simulation results,the performance of the ofDM system with the cooperative diversity accesses to a significant diversity gain.国家自然科学基金资助项目(60672046);福建省青年创新基金资助项目(2009J05155);厦门市科技计划项目(3502Z20093008);厦门大学“985”二期信息创新平台项