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摘要:基于通信技术的列车运行控制系统(CBTC)是铁路信号的发展方向,交频分复用
OFDM)是一种无线环境下的高速传输技术,它对高速列车控制信息传输中卞要受到的由于多
径传播引起的快衰落所产生的影响有很强的抵抗能力.本文首先介绍了OFDM技术的发展和
基本原理,然后在计算机上用M atlal〕对其性能进行了仿真,仿真中将OFDM与传统的单载波
调制方式—i1,交振幅调制( 1frQAM)对抗多径十扰的性能进行了比较,最后分析了一者的仿真结果.
-Abstract: Based
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OFDM的最新IEEE的文档,用于信道和载波频偏的联合估计算法,比较前沿-OFDM latest IEEE documents, for the channel and the joint carrier frequency offset estimation algorithm to compare the forefront of
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OFDM(正交频分复用)技术实际上是MCM(Multi-Carrier Modulation,多载波调制)的一种。其主要思想是,将信道分成若干正交子信道,将高速数据信号转换成并行的低速子数据流,调制到在每个子信道上进行传输。正交信号可以通过在接收端采用相关技术来分开,这样可以减少子信道之间的相互干扰(ICI)。每个子信道上的信号带宽小于信道的相关带宽,因此每个子信道上的可以看成平坦性衰落,从而可以消除符号间干扰。而且由于每个子信道的带宽仅仅是原信道带宽的一小部分,信道均衡变得相对容-OFDM (
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A MATLAB program has been written to investigate Orthogonal Frequency Division
Multiplexing (OFDM) communication systems. This program is valuable for future researchers
simulating systems that are too theoretically complex to analyze. Single-car
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正交频分复用(OFDM,Orthogonal Frequency Division Multiplexing)是一种多载波数字调制技术,也可以被当作一种复用技术。具有频谱利用率高、抗多径干扰等特点,OFDM系统能够有效地抵抗无线信道带来的影响,例如信道的频率选择性衰落,脉冲噪声和共信道干扰的影响。本文主要介绍了OFDM原理的相关知识。-The Orthogonal Frequency Division Multiplexing (OFDM, Orthogonal Frequency Divisi
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This a thesis about CARRIER FREQUENCY OFFSET RECOVERY FOR ZERO-IF OFDM RECEIVERS.rar. The zero intermediate
frequency receiver architecture has now become popular as it has both economic and
size advantages over the traditional superheterodyne ar
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channel estimation is single carrier frequency division multiple access also called as DFT spread OFDM.
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OFDM载波同步方法,对开发第四代通信系统的人来说,非常有用。-OFDM carrier frequency synchronization method, on the development of fourth generation communication system of people, very useful.
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:载波频率偏移是OFDM系统实现的关键问题之一。分析了OFDM 系统载频偏移估计的2
种算法,即利用循环前缀和训练序列方法。它们均为最大似然估计方法。分别讨论了它们的基本
思想、实现方法和仿真结果。可以看出基于循环前缀算法复杂度较小,精度不高,而基于训练序列
的算法有较高的估计精度,但降纸了系统传输效率。-Abstract:Carrier frequency ofset is one of the key problems in OFDM system.Two foundationa
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Differential Space-Time-Frequency Codes for
MB-OFDM UWB with Dual Carrier Modulation
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Orthogonal frequency-division multiplexing (OFDM) is a method of encoding digital data on multiple carrier frequencies.
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A semi blind technique for estimating the carrier frequency offset in OFDM communication systems is presented in this
paper. The fractional and integer frequency offsets are esti-mated by employing a few null subcarriers in the rst OFDM
sy
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一种新的突发OFDM传输系统定时和载波频率捕获联合算法-A new burst OFDM transmission system timing and carrier frequency acquisition combined algorithm
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提出一种全新的子载波调制方式盲识别算法,该算法利用OFDM子载波组的统计特性,然后通过推导得到新的基于混合高阶矩的特征量,使得到新的特征量不受信噪比、载波频偏与相位偏移的影响。
-Proposed a new sub-carrier modulation count Blind Identification
Method, the method using the statistical characteristics of the OFDM sub-carrier group, an
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OFDM Carrier Frequency
Offset Estimation
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A Novel Time and Frequency Synchronization Scheme for OFDM Systems
A new training symbol is designed and a novel
time and frequency synchronization scheme for orthogonal frequency division multiplexing systems is proposed. The time synchroniza
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OFDM is a multi-carrier transmission technique. It converts the frequency selective fading channel into a collection of parallel flat fading sub-channels which simplifies the structure of a receiver. OFDM has been widely used in communication system
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在现代无线通信技术中,扩频通信是一种具有较强抗干扰性能的技术,正交频分复用(OFDM)是一种具有较高数据传输速率和频谱利用率,并能有效对抗频率选择性衰落的多载波调制技术,因而将这二者结合起来构建系统势必会进一步提高系统的抗干扰和抗衰落性能,研究其结合技术也逐渐成为无线通信领域的热点。随着3G的兴起,即将推出的LTE也将采用OFDM技术(正交频分多路复用)。
由于OFDM的多载波特性,使得直接序列扩频技术和跳频技术能够与OFDM技术进行有效的结合。在本文中,我们研究了OFDM)以及相关抗干扰抗
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扩频通信在现代无线通信技术中是一种具有较强抗干扰性能的技术,正交频分复用(OFDM)一种具有较高数据传输速率和频谱利用率,并能有效对抗频率选择性衰落的多载波调制技术,因而将这二者结合起来构建系统势必会进一步提高系统的抗干扰和抗衰落性能,研究其结合技术也逐渐成为无线通信领域的热点。随着3G的兴起,即将推出的LTE也将采用OFDM技术(正交频分多路复用)。
由于OFDM的多载波特性,使得直接序列扩频技术和跳频技术能够与OFDM技术进行有效的结合。在本文中,我们研究了OFDM)以及相关抗干扰抗衰落
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OFDM的通用程序,多载波调制中的正交频分复用,文档中就是程序。-OFDM general procedures, multi-carrier modulation in the orthogonal frequency division multiplexing, the document is the program.
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