滤波多音调制系统中的同步技术研究

【作者】 王玮；

【导师】 高振明；

【作者基本信息】 山东大学 ， 通信与信息系统， 2006， 硕士

【摘要】 社会进步与全面信息化对通信提出了越来越高的要求，单纯的语音服务己经不能满足人们需要，能够通过无线网络随时随地获得多媒体业务的接入成为人们对通信技术的要求，而电子技术、多媒体技术、移动通信技术的发展使其成为可能。目前，在第三代移动通信系统(3G)走向商用化的情况下，下一代移动通信系统正成为研究的热点，其数据传输速率可以达到10Mbps至100Mbps，能有效地对抗多径衰落，具有非常高的频带利用率。 多载波传输技术(MCM)能够在保持较高信息传输速率的同时，有效地克服多径传播造成的符号间干扰(ISL)。正交频分复用(OFDM)作为一种多载波调制技术，成为下一代通信研究中的一个热点。其凭借信号本身的特点能够高速传输数据信息，有效地对抗多径衰落；但是它也存在许多需要解决的关键问题，如容易受频率偏移和相位噪声影响，有较大的峰值平均功率比(PAPR)等。这些问题都制约着OFDM在无线信道中的应用，现在人们对OFDM所进行的研究也主要集中在这些领域。 滤波多音调制(FMT)是基于滤波器组(filter banks)的多载波技术。该技术的主要特点是各子信道具有很高的频谱约束性，对系统频率偏差不敏感。FMT克服了OFDM易受频率偏差影响的弱点，但FMT系统需要引入子信道均衡技术来消除滤波器组的影响。 本文第一章首先概括介绍了无线信道的基本理论和多载波传输技术。 第二章介绍了滤波多音调制技术的基本原理、基本模型，给出了可实用的高效实现形式，对FMT和OFDM两种技术的子信道划分方式、系统实现结构、复杂度以及频谱利用率和抗干扰性能进行了比较。 第三章定量分析了定时偏差和载波频率偏差对FMT系统性能的影响。采用系统接收星座图和误比特率来衡量各种同步误差对FMT传输系统性能影响的大小。 第四章研究了FMT系统中的同步技术。针对FMT系统的特点，对现有的同步算法进行改进，提出了新的适合FMT系统的同步算法，并分析更多还原

【Abstract】 With the progress of the world, people need high quality and transmission rate of communications, and simple voice service can’t meet the requirement. It is possible to get multimedia service with wireless network at anytime and any places, for that electronic, multimedia and mobile communication has developed rapidly. Up to now, 3G has been launched into business in many countries, and researches are focus on the next generation communication system, called 4G. which is characteristic of the good resistance to multipath decay and high efficiency of frequency. The data rate of 4G is ranging from 10Mbps to 100Mbps.Multicarrier technique provides high data rate and efficiently avoiding intersymbol inference (ISI) arosing by multipath propagation. As one of the multicarrier techniques, OFDM has many advantages, such as high data rate and resisting multipath decay, and it has become a hot field in the researches of 4G. On the other hand, there are many problems of OFDM, for example: high sensitivity to frequency offset and great peak to average power ratio (PAPR), etc. All these issues restrict the applications of OFDM in wireless environments to some extent, so lots of researchers pay attention to them.Filtered Multitone (FMT) Modulation is a new multicarrier technology based on filter banks. In FMT system, the spectrum of each subchannel has a high level of spectral containment. So the interference of inter-channel (ICI) is negligible compared to other noise, while it often appears in OFDM system because of its sensitivity to frequency offset. However, sub-channel equalization is needed in order to reduce the remaining ISI introduced by the filter banks.In chapter 1, we provide a brief introduction of the characteristics of wireless channel, and MCM technology.In chapter 2, the principle of FMT. as well as its efficient implementation, are studied from its basic idea, system model.We compare these two different multicarrier techniques FMT and OFDM, with the way separating subchannels, structure of the system, complexity, efficiency of frequency and performance to interfere, including ISI and ICI.更多还原