Description: Multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) is very sensitive to the carrier frequency offset (CFO), which not only affects the channel estimation but also the selection of a minimum error probability based precoder for peak-to-average power ratio (PAPR) reduction such that the system performance will degrade. This paper presents the joint scheme of CFO) and channel estimation in the MIMO-OFDM systems with the minimum error probability based precoder for reducing PAPR. We provide the solution to eliminate the effects of ICI due to CFO mismatch for OFDM with space frequency block codes and spatial multiplexing, drive a generalized linear model and propose a non-iterative reduced complexity model.-Multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) is very sensitive to the carrier frequency offset (CFO), which not only affects the channel estimation but also the selection of a minimum error probability based precoder for peak-to-average power ratio (PAPR) reduction such that the system performance will degrade. This paper presents the joint scheme of CFO) and channel estimation in the MIMO-OFDM systems with the minimum error probability based precoder for reducing PAPR. We provide the solution to eliminate the effects of ICI due to CFO mismatch for OFDM with space frequency block codes and spatial multiplexing, drive a generalized linear model and propose a non-iterative reduced complexity model. Platform: |
Size: 1024 |
Author:sivadeep |
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Description: 对OFDM的载波频偏进行估计和补偿，采用ML最大似然估计算法，有不同频偏值和不同信噪比的仿真结果图。-For OFDM carrier frequency offset estimation and compensation, using ML maximum likelihood estimation, have different values and different SNR offset simulation results shown in Fig. Platform: |
Size: 38912 |
Author:tabase |
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Description: WIMAX_WZ_withencoding:信道估计，相位噪声补偿，频偏估计，编解码都有
WIMAX_WZ_withoutencoding：在上面的工程基础上，去掉编解码部分
WIMAX_WZ_withoutprocessing：在上面的工程基础上，再去掉相位噪声补偿，频偏估计
WIMAX_WZ_withoutprocessing2：在上面的工程基础上，改用新的前导和导频联合信道估计方案,参考文档《基于802_16d标准的OFDM信道估计技术的研究与实现.kdh》
因为白噪声信道仿真只能体现QPSK调制和RS-CC编码的性能，需要仿真SNR可控的SUI信道，来估计信道均衡的性能。
在多普勒频偏fd>100Hz时，联合信道估计性能才比前导估计强，否则前导估计性能更优。对于600MHz中心频率，要求收发机相对运动速度大于180km/h，这种情况出现的概率不大-WIMAX_WZ_withencoding: channel estimation, phase noise compensation, frequency estimation, the codec has WIMAX_WZ_withoutencoding: the project on the basis of the above, remove the codec section WIMAX_WZ_withoutprocessing: the project on the basis of the above, then remove the phase noise compensation, offset estimation WIMAX_WZ_withoutprocessing2: In the project on the basis of the above, use the new leader and pilot joint channel estimation scheme, the document " Standards-based 802_16d OFDM channel estimation and implementation of technology .kdh" because white noise channel simulation only reflects the QPSK modulation and RS-CC coding performance requires simulation SNR controllable SUI channel, to estimate the performance of channel equalization. When Doppler shift fd> 100Hz, joint channel estimation performance was stronger than the leading estimate, otherwise better estimation performance leader. For 600MHz center frequency transceiver requirements relative velocity Platform: |
Size: 40960 |
Author:陈茂 |
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Description: 接收端采用的算法和程序流程与发送端发送的OFDM符号的帧结构有关系。具体的帧结构，以及定时估计，频偏估计，剩余误差跟踪的算法可参考算法说明文档。这里对程序的流程进行说明。
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。
-The receiving end uses the algorithm and the program flow and the frame structure of the OFDM symbol transmitted by the sending end. Specific frame structure, and timing estimation, frequency offset estimation, residual error tracking algorithm can refer to the documentation. Here to illustrate the process of the program.
First, according to the characteristics of the short training word correlation operation, the signal reaches the detection, when the correlation value is greater than the threshold of a certain number of times, that there is a signal to reach. Then, according to the characteristics of the long training word, the correlation operation is carried out, and the initial position of the OFDM symbol FFT is estimated. The estimated position of the FFT window, first in the time domain for small frequency offset estimation, two long training word for small frequency offset compensation, the FFT operation. According to the result of FFT for integer frequency bias estimation. Af Platform: |
Size: 34816 |
Author:shinfer |
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Description: ML (maximum likelihood estimation) algorithm for OFDM frequency offset estimation in multi carrier communication Platform: |
Size: 1024 |
Author:stu陈 |
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Description: In a rapidly fading environment in high data rate wireless communication systems the orthogonality of OFDM sub carrier signals destroyed and this phenomenon potentially results in Inter carrier interference (ICI).The novel contribution of the paper is that, the effects of ICI have been analyzed and solutions to ICI diminution have been presented in different frequency offset values such as 0.5,0.15 and 0.30 . The first method is a self-cancellation scheme, in which redundant data is transmitted onto adjacent subcarriers such that the ICI between adjacent sub carriers cancels out at the receiver. The other technique the Extended Kalman Filter (EKF) method statistically estimate the frequency offset and correct the offset using the estimated value at the receiver-In a rapidly fading environment in high data rate wireless communication systems the orthogonality of OFDM sub carrier signals destroyed and this phenomenon potentially results in Inter carrier interference (ICI).The novel contribution of the paper is that, the effects of ICI have been analyzed and solutions to ICI diminution have been presented in different frequency offset values such as 0.5,0.15 and 0.30 . The first method is a self-cancellation scheme, in which redundant data is transmitted onto adjacent subcarriers such that the ICI between adjacent sub carriers cancels out at the receiver. The other technique the Extended Kalman Filter (EKF) method statistically estimate the frequency offset and correct the offset using the estimated value at the receiver Platform: |
Size: 211968 |
Author:Fardeen |
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Description: 完美的OFDM程序，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。-Perfect OFDM procedures, according to the characteristics of the short training word correlation operation, the signal reaching the detector, when the detected correlation value is greater than a certain threshold number of times that the signal arrives. Then according to the characteristics of the long training words, the correlation operation, to estimate the OFDM symbol FFT window starting position. The estimated position of the FFT window, the first in the time domain frequency offset estimate small, two small words long training frequency offset compensation after FFT operation, estimated integer frequency offset based on the result of the FFT operation. These parameter estimation is completed, the data can be demodulated. The first portion of the data of the complete frequency offset compensation, and then performs the FFT operation to obtain data in the frequency domain, demodulates the estimated FFT window position. Then extract the subcarrier corresponding to the pilot positio Platform: |
Size: 692224 |
Author:Jieni ZHANG |
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Description: 正交频分复用系统ofdm中传统的ml频偏估计算法-Orthogonal frequency division multiplexing system ofdm in the traditional ml frequency offset estimation algorithm Platform: |
Size: 1024 |
Author:李丽 |
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Search - frequency offset in ofdm