Description: OFDM通信系统调制解调 包括数字前端处理、卷积编码、峰均值抑制、符号定时、频偏检测、信道估计、相位补偿等-OFDM modulation and demodulation communication system including digital front-end processing, convolution coding, the mean peak inhibition, symbol timing, frequency offset detection, channel estimation, phase compensation Platform: |
Size: 119808 |
Author:宋巍 |
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Description: 信道的频率响应是时变的，设计最佳的固定的解调滤波是不可能的，因此，需要一种能补偿或减少接收信号中ISI的方法，这种ISI补偿方法称为均衡方法。
自适应均衡技术能够用来抵消由于信道带限或时间色散所导致的码间干扰，可以使通信系统更有效地利用信道带宽。
-Channel frequency response is time-varying, the best fixed design demodulation filter is impossible, therefore, need to be able to receive compensation or reduce the signal in the ISI method, the ISI compensation is called a balanced approach. Adaptive equalization techniques can be used to offset the channel band-limited or time dispersion caused by the inter-symbol interference can make communication systems more efficient use of channel bandwidth. Platform: |
Size: 4096 |
Author:高露洁 |
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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: 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: In this paper, we present and analyze efficient frame synchronization and frequency offset compensation scheme with ternary sequences for an orthogonal frequency division multiplexing (OFDM) system in Rayleigh fading channels. Frame
synchronization is an essential procedure for normal operation of
the OFDM system because of sensitivity to synchronization errors. And when there are frequency offsets in OFDM frame, the loss of
orthogonality occurs and the interference problem among several subcarriers is introduced. These fact leads to the requirement for joint implementation of the frame synchronization and frequency offset compensation. Platform: |
Size: 1581056 |
Author:Joel |
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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: zedboard/AD9361平台进行无线收发，在接收端进行频偏估计和补偿的Verilog参考代码。-zedboard/AD9361 platform for wireless transceiver, the receiver frequency offset estimation and compensation, you can refer to the Verilog code. Platform: |
Size: 1024 |
Author:何晨光 |
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Description: 一个相干光OFDM系统范例，其中包括频偏补偿、信道估计即色散补偿、相差估计、误码率计算等等。-A coherent optical OFDM system paradigm, including frequency offset compensation, channel estimation, namely the dispersion compensation, a phase difference estimation and error rate calculation, and so on. Platform: |
Size: 5120 |
Author:许林名 |
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Description: As each user in OFDMA based IEEE 802.16e network has different carrier frequencies, synchronization of carrier frequency offset (CFO) is a very complex task. The hardware implementation of the existing schemes is very expensive. Estimation and compensation are two steps to perform this operation. In this paper a combined estimation and compensation technique is proposed for IEEE 802.16e by using subcarriers. Platform: |
Size: 291840 |
Author:Ch.Manoj kumar |
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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: In distribution systems, the load has been a sudden
increase or decreases and it is like as nonlinear loads so the
load draw non-sinusoidal currents the AC mains and
causes the load harmonics and reactive power, and excessive
neutral currents that give pollution in power systems. Most
pollution problems created in power systems are due to the
nonlinear characteristics and fast switching of power
electronic devices. Shunt active filter based on current
controlled PWM converters are seen as a most viable solution.
This paper presents the harmonics and reactive power
compensation 3P4W micro-grid distribution system by
IP controlled shunt active. The technique which is used for
generate desired compensation current extraction based on
offset command instantaneous currents distorted or voltage
signals in the time domain because compensation time domain
response is quick, easy implementation and lower
computational load compared to the frequency domain.-In distribution systems, the load has been a sudden
increase or decreases and it is like as nonlinear loads so the
load draw non-sinusoidal currents the AC mains and
causes the load harmonics and reactive power, and excessive
neutral currents that give pollution in power systems. Most
pollution problems created in power systems are due to the
nonlinear characteristics and fast switching of power
electronic devices. Shunt active filter based on current
controlled PWM converters are seen as a most viable solution.
This paper presents the harmonics and reactive power
compensation 3P4W micro-grid distribution system by
IP controlled shunt active. The technique which is used for
generate desired compensation current extraction based on
offset command instantaneous currents distorted or voltage
signals in the time domain because compensation time domain
response is quick, easy implementation and lower
computational load compared to the frequency domain. Platform: |
Size: 14336 |
Author:hari |
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Description: 1、目标速度引起的失真，时间膨胀因子10%、chirp中心频率偏移5%。
2、超高速运动对脉冲压缩的影响，多普勒频移补偿(Distortion caused by target speed, time dilation factor 10%, and chirp center frequency offset 5%.
Effects of ultra high speed motion on pulse compression and Doppler frequency shift compensation) Platform: |
Size: 2048 |
Author:DVD发的v
|
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Search - frequency offset compensation