Description: 很完善的一个OFDM仿真程序,它以FUNCTION的形式,再现了OFDM映射,IDFTDFT,同步(时间频率同步)和信道估计,以及频率偏移的估计等一系列代码.-very sound one OFDM simulation program, which is in the form FUNCTION, Reproduction of OFDM mapping, IDFTDFT, synchronous (time-frequency synchronous) and channel estimation, and the estimated frequency offset a series of code. Platform: |
Size: 27733 |
Author:钟伟 |
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Description: 很完善的一个OFDM仿真程序,它以FUNCTION的形式,再现了OFDM映射,IDFTDFT,同步(时间频率同步)和信道估计,以及频率偏移的估计等一系列代码.-very sound one OFDM simulation program, which is in the form FUNCTION, Reproduction of OFDM mapping, IDFTDFT, synchronous (time-frequency synchronous) and channel estimation, and the estimated frequency offset a series of code. Platform: |
Size: 27648 |
Author:钟伟 |
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Description: 《MIMO-OFDM关键技术的研究和完整仿真平台的建立》，建立了一个完整的MIMO-OFDM的仿真平台，为实际的硬件平台提供解决方案，给出性能评估。为建立这个完整的仿真平台，本文从MIMO-OFDM信号模型，提出系统实现的各个关键技术:帧同步和载波频偏估计、信道估计、采样同步和载波跟踪、空时/频编解码。- MIMO-OFDM key technology research and the establishment of a complete simulation platform , the establishment of a complete MIMO-OFDM simulation platform, for the actual hardware platform to provide solutions, given performance evaluation. For the establishment of the integrity of the simulation platform, this article from the MIMO-OFDM signal model, the system in all key technologies: frame synchronization and carrier frequency offset estimation, channel estimation, sampling synchronization and carrier tracking, space-time/frequency codecs. Platform: |
Size: 2463744 |
Author:李继龙 |
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Description: 在这篇论文中，我们提出一种新的时间偏移估计方法应用于OFDM系统。这里提出的估计是为了避免发生在Schmidl中的时间偏移估计方法中的歧义。通过仿真，所提出方案中的性能以均值和最小均方误差的形式说明。仿真结果表明：它与其它估计器相比在相当大的程度上有更小的均方误差。-In this paper, we propose a new time offset estimation method is applied to OFDM systems. Estimates presented here took place in order to avoid the time Schmidl offset estimation method of ambiguity. Through the simulation, the proposed program of performance to the mean and minimum mean square error of the form. The simulation results show that: it is estimated that compared with the other to a large extent there is a smaller mean square error. Platform: |
Size: 91136 |
Author:hehe |
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Description: 以FUNCTION的形式,再现了OFDM映射,IDFTDFT,同步(时间频率同步)和信道估计,以及频率偏移的估计等一系列代码.-To FUNCTION in the form of, reproduce OFDM mapping, IDFTDFT, synchronized (time and frequency synchronization), and channel estimation and frequency offset estimation and a series of codes. Platform: |
Size: 17408 |
Author:王琴 |
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Description: In this paper, we investigate the timing and carrier
frequency offset (CFO) synchronization problem in decode and
forward cooperative systems operating over frequency selective
channels. A training sequence which consists of one orthogonal
frequency-division multiplexing (OFDM) block having a tile
structure in the frequency domain is proposed to perform synchronization.
Timing offsets are estimated using correlation-type
algorithms. By inserting some null subcarriers in the proposed tile
structure, we propose a computationally efficient subspace decomposition-
based algorithm for CFO estimation. The issue of optimal
tile length is studied both theoretically and through simulations.
By judiciously designing the tile size of the pilot, the proposed
algorithms are shown to have better performance, in terms of
synchronization errors and bit error rate, than the time-division
multiplexing-based training method and the computationally demanding
space-alternating generalized expectation-maximization Platform: |
Size: 985088 |
Author:ashish |
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Description: In this paper, we investigate the timing and carrier
frequency offset (CFO) synchronization problem in decode and
forward cooperative systems operating over frequency selective
channels. A training sequence which consists of one orthogonal
frequency-division multiplexing (OFDM) block having a tile
structure in the frequency domain is proposed to perform synchronization.
Timing offsets are estimated using correlation-type
algorithms. By inserting some null subcarriers in the proposed tile
structure, we propose a computationally efficient subspace decomposition-
based algorithm for CFO estimation. The issue of optimal
tile length is studied both theoretically and through simulations.
By judiciously designing the tile size of the pilot, the proposed
algorithms are shown to have better performance, in terms of
synchronization errors and bit error rate, than the time-division
multiplexing-based training method and the computationally demanding
space-alternating generalized expectation-maximization Platform: |
Size: 728064 |
Author:ashish |
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Description: 一个ofdm的matlab程序，可以实现ofdm的频率同步和时间同步，可以运行，可以出图-a program of ofdm system in matlab,can execute the frequency synchronization and time synchronization,it can run Platform: |
Size: 1024 |
Author:邢昊 |
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Description: plotting Consecutive OFDM Subcarriers in Time domain..This program plots sensitivity of OFDM subcarriers with Carrier frequency offset(CFO)-plotting Consecutive OFDM Subcarriers in Time domain..This program plots sensitivity of OFDM subcarriers with Carrier frequency offset(CFO).. Platform: |
Size: 1024 |
Author:murugan |
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Description: MIMO OFDM 技术将成为第4 代移动通信系统的关键技术, 因MIMO OFDM 对时间和频率偏移非常敏感,
因此MIMO OFDM 同步显得尤为重要。提出了一种新的MIMO OFDM 定时同步和频偏同步技术。以GCL 序列为基础设
计了一个新的符合MIMO OFDM 同步技术的导频序列, 通过对该导频序列进行2 次相关得到频率估计, 并将所得频率
运用到定时同步中, 得到更为准确的时间估计。仿真结果表明, 在相同的信噪比情况下, 该方法可以使得系统的误码
率和帧传送误码率相对传统方法得到进一步减小。-MIMO OFDM will become a key technology of the fourth generation mobile communications system. However, MIMO OFDM is
sensitive to the CFO and timing synchronization, so the MIMO OFDM synchronization technology is very important. This paper proposes an
accurate technique for timing and frequency synchronization of multiple input multiple output ( MIMO ) orthogonal frequency division
multiplexing ( OFDM) systems. The technique derives a new preamble signal based on GCL sequences, according with the MIMJO OFDM
synchronization. The carrier frequency offset ( CFO) estimation is obtained through taking double correlation operations on the preamble signal,
and used in the timing synchronization to gain accurate time estimation. The simulation results show that at the same SNR, the proposed method
can reduce the BER and the frame transmission BER of the system compared to the conventional method. Platform: |
Size: 408576 |
Author:蜡笔 |
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Description: 频率同步是宽带OFDM系统中的关键技术，IEEE 802.11a 采用OFDM技术，利用其前导序列的重复结构，提出了一种分步的粗细频偏捕获与校正算法，同时为了补偿时域同步后的残余相差和适应信道的时变特性，还提出了一种基于频域导频的相位跟踪方案-Frequency synchronization is a key technology in the broadband OFDM systems, IEEE 802.11a uses OFDM technology, the use of the repetitive structure of the leader sequence, the thickness of a step frequency offset capture and correction algorithm, when the order to compensate at the same time domain synchronous residualthe difference between and adapt to the time-varying characteristics of the channel is also proposed based on frequency domain pilot phase tracking scheme Platform: |
Size: 858112 |
Author:Chaos |
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Description: 首先根据短训练字的特性进行相关运算，进行信号到达检测，当检测到相关值大于门限一定次数后，认为有信号到达。然后根据长训练字的特性，进行相关运算，进行OFDM符号FFT窗口起始位置的估计。估计出FFT窗口的位置后，先在时域进行小频偏的估计，将两个长训练字进行小频偏补偿后，进行FFT运算，根据FFT运算的结果进行整数倍频偏的估计。这些参数估计完成后，就可以进行数据解调了。先对数据部分进行完整的频偏补偿，然后根据估计的FFT窗口位置进行FFT运算得到频域的数据，进行解调。然后在对应于导频的子载波位置上提取出导频信息，根据导频信息估计出剩余定时误差以及剩余的信道响应误差，将误差量送入环路进行跟踪。当收到所有数据后，重新回到信号到达检测状态，进行下一次信号到达的检测和信号接收。-First of all, according to the characteristics of the short training word correlation calculation of the signal reaching the detector, when the detected correlation value is greater than the threshold of a certain frequency and that a signal arrives. Then, the correlation calculation according to the characteristics of the long training word, the initial estimate of the location of the OFDM symbol FFT window. The estimated position of the FFT window, the first small frequency offset estimation in the time domain, the small frequency offset compensation, the two long training word FFT operation integer frequency offset estimate, according to the result of the FFT operation. After the completion of these parameter estimates, data demodulation. The complete frequency offset compensation, and then based on the estimated FFT window position for the FFT operation to obtain a frequency domain data, demodulates the first data part. Then in a position corresponding to the pilot subcarriers extr Platform: |
Size: 124928 |
Author:章田 |
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Description: 一种新的符号定时和载波频率同步算法,该算法将OFDM符号分成几部分。它使用相关性和积累在几个OFDM
符号获得估计函数。当部分的长度小于ISI自由地区,该算法可以识别它。然后估计的最优符号定时和载波频率偏移可以获得。计算机仿真结果表明,该算法不仅可以跟踪时变信道变化但也有较小的MSE比ML估计算法。-A new symbol timing and carrier frequency synchronization algorithm is presented and the algorithm divides the OFDM symbol into several parts. It uses correlation and accumulation in several OFDM
symbols to acquire estimation function. When the length of part is smaller than that of ISI free region , the algorithm can distinguish it. Then the estimation of optimal symbol timing and carrier frequency offset can be acquired .The computer simulation results show that the proposed algorithm not only can track time varying channel change but also has smaller MSE than that of ML
estimation algorithm. Platform: |
Size: 276480 |
Author:wujueying |
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Description: 首先根据短训练字的特性进行相关运算，进行信号到达检测，当检测到相关值大于门限一定次数后，认为有信号到达。然后根据长训练字的特性，进行相关运算，进行OFDM符号FFT窗口起始位置的估计。估计出FFT窗口的位置后，先在时域进行小频偏的估计，将两个长训练字进行小频偏补偿后，进行FFT运算，根据FFT运算的结果进行整数倍频偏的估计。这些参数估计完成后，就可以进行数据解调了。先对数据部分进行完整的频偏补偿，然后根据估计的FFT窗口位置进行FFT运算得到频域的数据，进行解调。然后在对应于导频的子载波位置上提取出导频信息，根据导频信息估计出剩余定时误差以及剩余的信道响应误差，将误差量送入环路进行跟踪。当收到所有数据后，重新回到信号到达检测状态，进行下一次信号到达的检测和信号接收。-First, according to the characteristics of the short training word correlation operation, the signal reaching the detector, when the detected correlation value is greater than the threshold after a certain number of times that a signal arrives. And then the characteristics of long training word, the correlation operation for the FFT window starting position of an OFDM symbol estimate. The estimated position of the FFT window, the first small frequency offset in the time domain estimation, the two long training word small frequency offset compensation, the FFT operation, the FFT result of the operation for integer frequency offset estimate. These parameter estimation is completed, the data can be demodulated on. The first portion of the data for a complete frequency offset compensation, and based on the estimated FFT window position of the FFT operation to obtain frequency domain data, demodulated. Then corresponding to the position of the pilot subcarriers are extracted on pilot inform Platform: |
Size: 11264 |
Author:wangkai |
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Description: 基于matlab的OFDM仿真程序；
我再论坛找了很多OFDM的代码和文章,但总有遗患,为什么呢原因是大部分只有简单的映射,IDFTDFT变换等等,但主要的同步和信道估计去没有人提出来,甚至做出来..
现在我终于找到了一份,它以FUNCTION的形式,再现了OFDM映射,IDFTDFT,同步(时间频率同步)和信道估计,以及频率偏移的估计等一系列代码.-Based on the OFDM matlab simulation program I' ll find a lot of forums and articles OFDM code, but there are left suffering, why because most only simple mapping, IDFTDFT transformation, etc., but the main synchronization and channel estimation to no one proposed, and even do it .. and now I finally found a copy of it in the form FUNCTION, Reproduction of OFDM mapping, IDFTDFT, synchronous (time and frequency synchronization) and channel estimation, and the estimated frequency offset a series of code. Platform: |
Size: 26624 |
Author:qinxuechen |
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Description: 时间同步后即可确定每帧数据的起始位置，这样就能完整的截取下每一帧。但是，数据中还带有频偏信息。在常规的通信系统中，多普勒很小仅仅会带来很小的频偏，但是在大多普勒的情况下，频偏将非常大，20马赫的速度将会带来将近34K的频偏。因此，如何很好的纠正频偏即为本系统的难点。
OFDM中，我们将大于子载波间隔倍数的频偏称为整数倍频偏，而将小于一个子载波间隔的频偏称为小数倍频偏。频偏矫正精度只要能保证小于十分之一倍的子载波间隔，频偏就不会对均衡和解调造成影响。本文中我们借鉴这种思想，由于硬件资源限制，我们将在接收端做64点FFT，即相当于将频域划分为64份，我们将小于 的频偏称为小数倍频偏，将 整数倍的频偏称为整数倍频偏。本程序即基于SCHIMDL经典方法完成小数倍频偏纠正-After time synchronization can determine the starting position of each frame data, so you can complete the interception of each frame. However, in the data with frequency information. In conventional communication systems, doppler small will bring only small deviation, but in the case of most of the doppler, frequency PianJiang is very large, 20 Mach speed will lead to deviation of nearly 34 k. Therefore, how to good to correct deviation is the difficulty of this system.
OFDM, we will be bigger than the sub-carrier spacing ratio of frequency deviation is called the integer frequency offset, and the interval will be less than a child carrier frequency offset is called decimal frequency doubling. Deviation is less than one over ten times as long as can guarantee accuracy of sub-carrier spacing, deviation will not affect balance and demodulation. This article, we draw lessons from the idea, due to the limited hardware resources, we will do 64 points FFT at the receiving end, which is equ Platform: |
Size: 14402560 |
Author:Nico_S |
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Description: 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 synchronization is accomplished by using the symmetric conjugate of the training symbol in time domain and the frequency synchronization is finished by utilizing the good
autocorrelation of the training symbol in frequency domain.
The simulation results show that compared with conventional schemes, the proposed scheme gives a more accurate estimate of symbol timing and carrier frequency offset and provides a
wider acquisition range for the carrier frequency offset.1 Platform: |
Size: 321536 |
Author:Mohamed |
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Search - TIME OFFSET IN ofdm