OFDM 根据短训练字的特性进行相关运算,进行信号到达检测我要分享

OFDM

OFDM FFT 信号检测

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文件大小: 122KB

代码分类: 信号处理

开发平台: matlab

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代码描述

中文说明:

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。


English Description:

Firstly, according to the characteristics of the short training word, the correlation operation is carried out to detect the signal arrival. When the correlation value is greater than the threshold for a certain number of times, the signal is considered to have arrived. Then, according to the characteristics of the long training word, correlation operation is carried out to estimate the start position of OFDM symbol FFT window. After the position of FFT window is estimated, the small frequency offset is estimated in the time domain. After the two long training words are compensated for small frequency offset, the FFT operation is performed, and the integer multiple frequency offset is estimated according to the results of FFT operation. After these parameters are estimated, the data can be demodulated. Firstly, complete frequency offset compensation is carried out for the data part, and then FFT operation is performed according to the estimated FFT window position to obtain the frequency domain data for demodulation. Then the pilot information is extracted from the subcarrier position corresponding to the pilot. According to the pilot information, the residual timing error and the residual channel response error are estimated, and the error is sent to the loop for tracking. After receiving all the data, the system will return to the signal arrival detection state again to detect and receive the next signal arrival.


代码预览

OFDM-MATLAB

...........\OFDM_rece_matlab

...........\................\data_I_train_word_1_i0_256.txt

...........\................\data_I_train_word_2_i0_256.txt

...........\................\data_I_train_word_re_i0_256.txt

...........\................\data_Q_train_word_1_i0_256.txt

...........\................\data_Q_train_word_2_i0_256.txt

...........\................\data_Q_train_word_re_i0_256.txt

...........\................\OFDM_mod_I_ser_2up_sam_50.dat

...........\................\OFDM_mod_original_data_I_ser_2up_sam_50.dat

...........\................\OFDM_mod_original_data_Q_ser_2up_sam_50.dat

...........\................\OFDM_mod_Q_ser_2up_sam_50.dat

...........\................\v06_03_dem_2up_arrange.m

...........\OFDM_send_matlab

...........\................\data_I_train_word_1_i0_256.txt

...........\................\data_I_train_word_2_i0_256.txt

...........\................\data_I_train_word_re_i0_256.txt

...........\................\data_Q_train_word_1_i0_256.txt

...........\................\data_Q_train_word_2_i0_256.txt

...........\................\data_Q_train_word_re_i0_256.txt

...........\................\HBF23.txt

...........\................\I1.txt

...........\................\I2.txt

...........\................\I3.txt

...........\................\I4.txt

...........\................\ofdm_mod.m

...........\................\SoutI_4_BF.txt

...........\................\SoutI_4_IF.txt

...........\程序流程说明.doc