OFDM通信系统matlab仿真

%main_OFDM.m %这是一个相对完整的OFDM通信系统的仿真设计，包括编码，调制，IFFT， %上下变频，高斯信道建模，FFT，PAPR抑制，各种同步，解调和解码等模 %块，并统括系统性能的仿真验证了系统设计的可靠性。 clear all close all clc %++++++++++++++++++++++++++全局变量++++++++++++++++++++++++++++++ % seq_num 表示当前帧是第几帧 % count_dds_up 上变频处的控制字的累加 % count_dds_down 下变频处的控制字的累加（整整） % count_dds_down_tmp 下变频处的控制字的累加（小数） % dingshi 定时同步的定位 % m_syn 记录定时同步中的自相关平台 global seq_num global count_dds_up global count_dds_down global count_dds_down_tmp global dingshi global m_syn %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ % SNR_Pre 设定用于仿真的信噪比的初值 % interval_SNR 设定用于仿真的信噪比间隔 % frame_num 每一个信噪比下仿真的数据帧数 % err_int_final 用于计算每帧出现的误比特数 % fwc_down 设定的接收机初始载波频率控制字 % fre_offset 设定接收机初始载波频率偏移调整量（单位为Hz） % k0 每次进入卷积编码器的信息比特数 % G 卷积编码的生成矩阵 SNR_Pre=-5; interval_SNR=1; for SNR_System=SNR_Pre:interval_SNR:5 frame_num=152; dingshi=250; err_int_final=0; fwc_down=16.050; fre_offset=0; k0=1; G=[1 0 1 1 0 1 1;1 1 1 1 0 0 1 ]; disp('--------------start-------------------'); for seq_num=1:frame_num, %frame_num 帧数 %+++++++++++++++++++++++以下为输入数据部分+++++++++++++++++++++++ datain=randint(1,90); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %++++++++++++++++++++++以下为信道卷积编码部分+++++++++++++++++++++ encodeDATA=cnv_encd(G,k0,datain); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %+++++++++++++++++++++++++++信道交织编码+++++++++++++++++++++++++ interlacedata=interlacecode(encodeDATA,8,24); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %+++++++++++++++++++++++++以下为QPSK调制部分+++++++++++++++++++++ QPSKdata=qpsk(interlacedata); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %+++++++++++++++++++++++++++生成训练序列+++++++++++++++++++++++++ if seq_num<3 trainsp_temp=seq_train(); end %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %++++++++++++++++++++++++++++插入导频++++++++++++++++++++++++++++ PILOT=(1+j); m_QPSKdata=QPSKdata; data2fft_temp=[m_QPSKdata(1:8),PILOT,m_QPSKdata(9:16),PILOT,m_QPSKdata(17:24),PILOT,m_QPSKdata(25:32),PILOT,m_QPSKdata(33:40),PILOT,m_QPSKdata(41:48),m_QPSKdata(49:56),PILOT,m_QPSKdata(57:64),PILOT,m_QPSKdata(65:72),PILOT,m_QPSKdata(73:80),PILOT,m_QPSKdata(81:88),PILOT,m_QPSKdata(89:end)]; %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ trainsp_temp2=[trainsp_temp,zeros(1,128)]; trainsp=[trainsp_temp2(65:256),trainsp_temp2(1:64)]; %++++++++++++++++++++++++++降PAPR矩阵变换++++++++++++++++++++++++ matix_data=nyquistimp_PS(); matrix_mult=data2fft_temp*matix_data; %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ data2fft2=[matrix_mult(65:128),zeros(1,128),matrix_mult(1:64)]; %++++++++++++++++++++++++++++ifft运算+++++++++++++++++++++++++++ if seq_num==1 ifftin=trainsp; elseif seq_num==2 ifftin=trainsp; else ifftin=data2fft2; end IFFTdata=fft_my(conj(ifftin)/256); IFFTdata=conj(IFFTdata); % figure % plot(real(IFFTdata)) % xlabel('realIFFTdata') % figure % plot(imag(IFFTdata)) % xlabel('imagIFFTdata') %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %+++++++++++++++++++以下为插入循环前后缀，2倍升采样+++++++++++++++ data2fir=add_CYC_upsample(IFFTdata,2); % ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ % +++++++++++++++++++++++++fir低通滤波++++++++++++++++++++++++++ guiyi_a=[0.0017216 0.010162 0.025512 0.028801 -0.0059219 -0.060115 -0.0496 0.091431 0.29636 0.3956 0.29636 0.091431 -0.0496 -0.060115 -0.0059219 0.028801 0.025512 0.010162 0.0017216 ]; %抽样截止频率为128kHZ,通带截止频率为20kHZ，阻带截止频率为40kHZ，带内纹波动小于1dB，带外衰减100dB txFIRdatai=filter(guiyi_a,1,real(data2fir)); txFIRdataq=filter(guiyi_a,1,imag(data2fir)); % ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %+++++++++++++++++++++++++发射机cic滤波++++++++++++++++++++++++++ CICidatai=cic_inter(txFIRdatai,20); CICidataq=cic_inter(txFIRdataq,20); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %+++++++++++++++++++++++++++++上变频++++++++++++++++++++++++++++ fwc_up=16; %控制字可以选择 DUCdata=up_convert_ofdm(fwc_up,CICidatai,CICidataq); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %++++++++++++++++++++++++++高斯白噪声信道++++++++++++++++++++++++ [DUCdata,datamax]=guiyi_DUCdata(DUCdata); awgn_data=awgn(DUCdata,SNR_System); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %*****************************接受机***************************** %+++++++++++++++++++++++++++++下变频+++++++++++++++++++++++++++++ DUCdata_tmp=awgn_data; fwc_down=fwc_down+(fre_offset*128/2560000); r_fre_offset=2560000*((fwc_down-fwc_up)/128); [DDCdatai,DDCdataq]=down_convert_ofdm(fwc_down,DUCdata_tmp); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %++++++++++++++++++++++++++接收机cic滤波+++++++++++++++++++++++++ CICddatai=cic_deci(DDCdatai,40,40); CICddataq=cic_deci(DDCdataq,40,40); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %++++++++++++++++++++++++++++fir低通滤波++++++++++++++++++++++++ guiyi_b=[ 0.019527 -0.03934 0.049055 -0.018102 -0.1003 0.5944 0.5944 -0.1003 -0.018102 0.049055 -0.03934 0.019527]; %抽样截止频率为64kHZ,通带截止频率为20kHZ，阻带截止频率为30kHZ，带内纹波动小于1dB，带外衰减60dB rxFIRdatai=filter(guiyi_b,1,CICddatai); rxFIRdataq=filter(guiyi_b,1,CICddataq); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %+++++++++++++++++++++++++++++++量化++++++++++++++++++++++++++++ q_rxFIRdatai=sign(rxFIRdatai); q_rxFIRdataq=sign(rxFIRdataq); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %++++++++++++++++++++++++++++定时同步检测++++++++++++++++++++++++ if seq_num<3 time_syn(q_rxFIRdatai,q_rxFIRdataq); end %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %+++++++++++++++++++++++++++++频率同步+++++++++++++++++++++++++++ fre_offset=fre_syn(rxFIRdatai,rxFIRdataq); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %+++++++++++++++++++++++++++++fft运算+++++++++++++++++++++++++++ if seq_num>2 seq_num-2 fftw=32+dingshi; rxFIRdata_syn=rxFIRdatai(fftw:fftw+255)+j*rxFIRdataq(fftw:fftw+255); FFTdata=fft_my(rxFIRdata_syn); %++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %++++++++++++++++++++++++++降PAPR逆矩阵变换++++++++++++++++++++++ fftdata_reg=[FFTdata(193:256),FFTdata(1:64)]; dematrix_data=fftdata_reg*pinv(matix_data); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %++++++++++++++++++++++++++++相位补偿+++++++++++++++++++++++++++ rx_qpsk_din_th=phase_comp(dematrix_data); %+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %+++++++++++++++++++++++++++QPSK解调部分++++++++++++++++++++++++ % figure % plot(rx_qpsk_din_th,'.') % xlabel('星座图') datatemp4=deqpsk(rx_qpsk_din_th); datatemp4=sign(datatemp4); for m=1:192 if datatemp4(m)==-1 datatemp4(m)=1; elseif datatemp4(m)==1 datatemp4(m)=0; end end %++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %+++++++++++++++++++++++++信道解交织++++++++++++++++++++++++++++ interdout=interlacedecode(datatemp4,8,24); %++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %++++++++++++++++++++以下为viterbi译码部分++++++++++++++++++++++ decodeDATA=viterbi(G,k0,interdout); %++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ %++++++++