OFDM matlab源程序.docx
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OFDMmatlab源程序
%main_OFDM.m
%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。
clearall
closeall
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
globalseq_num
globalcount_dds_up
globalcount_dds_down
globalcount_dds_down_tmp
globaldingshi
globalm_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;
forSNR_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=[1011011;1111001];
disp（'--------------start-------------------'）;
forseq_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+++++++++++++++++++++++++
ifseq_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+++++++++++++++++++++++++++
ifseq_num==1
ifftin=trainsp;
elseifseq_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=[0.00172160.0101620.0255120.028801-0.0059219-0.060115-0.04960.0914310.296360.39560.296360.091431-0.0496-0.060115-0.00592190.0288010.0255120.0101620.0017216];
%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=[0.019527-0.039340.049055-0.018102-0.10030.59440.5944-0.1003-0.0181020.049055-0.039340.019527];
%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++++++++++++++++++++++++
ifseq_num<3
time_syn（q_rxFIRdatai,q_rxFIRdataq）;
end
%+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%+++++++++++++++++++++++++++++频率同步+++++++++++++++++++++++++++
fre_offset=fre_syn（rxFIRdatai,rxFIRdataq）;
%+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%+++++++++++++++++++++++++++++fft运算+++++++++++++++++++++++++++
ifseq_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）;
form=1:
192
ifdatatemp4（m）==-1
datatemp4（m）=1;
elseifdatatemp4（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）;
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%+++++++++++++++++++++++++误比特统计++++++++++++++++++++++++++++
err_final=sum（abs（decodeDATA-datain））
err_int_final=err_int_final+err_final
end
end
disp（'------------------------------------------------------'）;
SNR_System
err_rate_final（（SNR_System-SNR_Pre）./interval_SNR+1）=err_int_final/（90*（frame_num-2））
disp（'------------------------------------------------------'）;
end
disp（'--------------end-------------------'）;
SNR_System=SNR_Pre:
interval_SNR:
5;
figure
semilogy（SNR_System,err_rate_final,'b-*'）;
xlabel（'信噪比/dB'）
ylabel（'误码率'）
axis（[-5,5,0,1]）
gridon
%+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%************************beginningoffile*****************************
%cnv_encd.m
%卷积码编码程序
functionoutput=cnv_encd（G,k0,input）
%cnv_encd（G,k0,input）,k0是每一时钟周期输入编码器的bit数，
%G是决定输入序列的生成矩阵，它有n0行L*k0列n0是输出bit数，
%参数n0和L由生成矩阵G导出，L是约束长度。
L之所以叫约束长度
%是因为编码器在每一时刻里输出序列不但与当前输入序列有关，
%而且还与编码器的状态有关，这个状态是由编码器的前（L-1）k0。
%个输入决定的,通常卷积码表示为（n0,k0,m），m=（L-1）*k0是编码
%器中的编码存贮个数，也就是分为L-1段，每段k0个
%有些人将m=L*k0定义为约束长度，有的人定义为m=（L-1）*k0
%查看是否需要补0，输入input必须是k0的整数部
%+++++++++++++++++++++++variables++++++++++++++++++++++++++++
%G决定输入序列的生成矩阵
%k0每一时钟周期输入编码器的bit数
%input输入数据
%output输入数据
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
ifrem（length（input）,k0）>0
input=[input,zeros（size（1:
k0-rem（length（input）,k0）））];
end
n=length（input）/k0;
%检查生成矩阵G的维数是否和k0一致
ifrem（size（G,2）,k0）>0
error（'Error,Gisnotoftherightsize.'）
end
%得到约束长度L和输出比特数n0
L=size（G,2）/k0;
n0=size（G,1）;
%在信息前后加0，使存贮器归0，加0个数为（L-1）*k0个
u=[zeros（size（1:
（L-1）*k0））,input,zeros（size（1:
（L-1）*k0））];
%得到uu矩阵,它的各列是编码器各个存贮器在各时钟周期的内容
u1=u（L*k0:
-1:
1）;
%将加0后的输入序列按每组L*k0个分组，分组是按k0比特增加
%从1到L*k0比特为第一组，从1+k0到L*k0+k0为第二组，。
。
。
。
，
%并将分组按倒序排列。
fori=1:
n+L-2
u1=[u1,u（（i+L）*k0:
-1:
i*k0+1）];
end
uu=reshape（u1,L*k0,n+L-1）;
%得到输出，输出由生成矩阵G*uu得到
output=reshape（rem（G*uu,2）,1,n0*（L+n-1））;
%************************endoffile***********************************
%************************beginningoffile*****************************
%interlacecode.m
functiondout=interlacecode（din,m,n）
%实现信道的交织编码
%din为输入交织编码器的数据，m，n分别为交织器的行列值
%+++++++++++++++++++++++variables++++++++++++++++++++++++++++
%din输入数据
%m交织器的行值
%n交织器的列值
%dout输出数据
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
forj=1:
m
temp（j,:
）=din（j*n-（n-1）:
j*n）;
end
dout_temp=reshape（temp,1,length（din））;
dout=dout_temp（1:
end）;
%************************endoffile**********************************
%************************beginningoffile*****************************
%qpsk.m
%QPSK调制映射
functiondout=qpsk（din）
%+++++++++++++++++++++++variables++++++++++++++++++++++++++++
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