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基于Zadoff-Chu序列的水声通信同步算法
Synchronization Algorithm Based on Zadoff-Chu Sequences for Underwater Acoustic Communications
【作者】 李云飞；
【导师】 王易因；
【作者基本信息】 上海交通大学 ， 控制科学与工程， 2018， 硕士
【摘要】 水声通信作为人类探索、开发海洋过程中不可或缺的水下通信方式,逐步展现出其重要的研究价值和科研地位。在水声通信中,同步算法更是一个热门的研究方向。同步算法的作用在于帮助接收端估计定时偏差、频率偏差,确定信号中各符号的起始位置,进而准确地解调信号。然而,水声通信的同步工作面临着巨大的挑战。水声信道具有长传输时延、多径效应和多普勒效应明显等特点,它会对信号造成符号间干扰、子载波间干扰、载波频率偏移等负面影响,极大地增加了同步工作的难度。因此,设计一种针对水声信道特性的同步技术,是当前研究的一大热点,同时也是本文科研工作的目的之一。本文主要针对水声通信中的同步训练序列和同步算法进行了设计和研究。本文首先通过分析各类同步技术,引入了基于同步训练序列的同步算法;研究分析水声信道的特点,并且引用了本文所使用的水声信道模型;在介绍Zadoff-Chu序列的概念及其优秀特性后,基于该序列设计了同步训练序列的结构和参数,使之能够有效抵抗水声信道的干扰;在该同步训练序列的基础上,设计了与之相配合的接收端同步算法,能对信道的各项参数做有效的估计,并通过仿真实验验证了训练序列和同步算法的有效性和精度;参与设计开发了一款水声通信机,并基于该通信机设计了能够实现跨介质通信的实验平台。
【Abstract】 As one necessary underwater communication technique while human beings explore and develop the ocean,underwater acoustic communication starts to show its important value in the scientific research.In all the underwater acoustic communication techniques,the synchronization algorithm is one popular topic.The synchronization algorithm aims to help the receiver estimate the timing offset and the frequency offset,as well as locate the starting points of the symbols in the signal in order to demodulate the signal correctly.However,the development of the synchronization algorithm faces great challenges.The underwater acoustic channel has long propagation delay,multi-path effect and Doppler scaling effect,which results in inter-symbol interference,inter-carrier interference and carrier frequency offset and raises the difficulty of synchronization.Therefore,it’s a popular topic and one of my aims to design a synchronization technique which fits the underwater acoustic channel.In this article,we design and study the training sequence and the synchronization algorithm.Firstly,we discuss various synchronization techniques,introduce the synchronization algorithm based on the training sequence.We study the characteristics of the underwater acoustic channel and establish the acoustic model that we use in this article.After introducing the Zadoff-Chu sequence,we design the structure and parameter of the training sequence to help resist the interference caused by the channel.Based on the training sequence,we introduce the synchronization algorithm used in the receiver,which can estimate the parameters of the channel effectively.Simulation results prove the effectiveness and accuracy of the algorithm.We design a underwater acoustic modem and design a platform with the ability to communicate between the air and the underwater.