OFDM.rar.rar_OFDM好写吗_ofdm 信道估计_信道估计_信道估计 matlab

clear; % hold on; para=768;% number of used subcarriers fftlen=1024;% fft length noc=1024;% number of subcarriers nd=36;% number of information ofdm symbol for one loop np=4;% number of pilot symbol nloop=2;% number of simulation loops %%%%%%%%%%%%%%%%%%导频符号%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% pilot_symbol = [1-j, 1-j, -1-j, 1+j, 1-j, 1-j, -1+j, 1-j, 1-j, 1-j, 1+j, -1-j, 1+j, 1+j, -1-j, 1+j, -1-j, -1-j, 1-j, -1+j, 1-j, 1-j, -1-j, 1+j, 1-j, 1-j, -1+j, 1-j, 1-j, 1-j, 1+j, -1-j, 1+j, 1+j, -1-j, 1+j, -1-j, -1-j, 1-j, -1+j, 1-j, 1-j, -1-j, 1+j, 1-j, 1-j, -1+j, 1-j, 1-j, 1-j, 1+j, -1-j, 1+j, 1+j, -1-j, 1+j, -1-j, -1-j, 1-j, -1+j, 1+j, 1+j, 1-j, -1+j, 1+j, 1+j, -1-j, 1+j, 1+j, 1+j, -1+j, 1-j, -1+j, -1+j, 1-j, -1+j, 1-j, 1-j,1+j, -1-j, -1-j, -1-j, -1+j, 1-j, -1-j, -1-j, 1+j, -1-j, -1-j, -1-j, 1-j, -1+j, 1-j, 1-j, -1+j, 1-j, -1+j,-1+j, -1-j, 1+j, -1-j, 1+j, -1+j, -1+j, -1-j, 1+j, 1+j, 1+j, -1-j, 1+j, 1-j, 1-j, 1-j, -1+j, -1+j, -1+j, -1+j, 1-j, -1-j, -1-j, -1+j, 1-j, 1+j, 1+j, -1+j, 1-j, 1-j, 1-j, -1+j, 1-j, -1-j, -1-j, -1-j, 1+j,1+j, 1+j, 1+j, -1-j, -1+j, -1+j, 1+j, -1-j, 1-j, 1-j, 1+j, -1-j, -1-j, -1-j, 1+j, -1-j, -1+j, -1+j, -1+j, 1-j, 1-j, 1-j, 1-j, -1+j, 1+j, 1+j, -1-j, 1+j, -1+j, -1+j, -1-j, 1+j, 1+j, 1+j, -1-j, 1+j, 1-j, 1-j, 1-j, -1+j, -1+j, -1+j, -1+j, 1-j, -1-j, -1-j, 1-j, -1+j, -1-j, -1-j, 1-j, -1+j, -1+j, -1+j, 1-j, -1+j,1+j, 1+j, 1+j, -1-j, -1-j, -1-j, -1-j, 1+j, 1-j, 1-j]; pilot_symbol = [pilot_symbol, pilot_symbol]; pilot_symbol = pilot_symbol(1:384); pilot_symbol = [pilot_symbol, pilot_symbol]; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% delay=[0 2 4 6]; amp=[0 -2 -10 -20]; ml=2;% modulation level:QPSK sr=15625;% ofdm symbol rate br=sr.*ml;% bit rate per carrier gilen=128;% length of guard interval k=0:10; for l=1:length(k) ebn0=k(l); % ebn0 = 10; noe=0;% number oferror data nod=0;% number of transmitted data eop=0;% number of error packet nop=0;% number of transmitted packet noe2=0; for iii=1:nloop seridata=randint(1,para*(nd-np)); %%%%%%%%%%%%%%%%%%%%channel code%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% conved_bit0=zeros(1,para*(nd-np)*2); for n=1:(nd-np) conved_bit0(1,(n-1)*para*2+1:n*para*2)= co_dec(seridata(1,(n-1)*para+1:n*para),1);%%%%%%卷积编码%%%%%% conved_bit(1,(n-1)*para*2+1:n*para*2)=inter_sc(conved_bit0(1,(n-1)*para*2+1:n*para*2),1);%%%%%%%%%%%%交织%%%%%%%%%% end %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% paradata=reshape(conved_bit,para,(nd-np)*ml); a=zeros(para,nd*ml); a(:,3:18)=paradata(:,1:16); a(:,21:36)=paradata(:,17:32); a(:,39:54)=paradata(:,33:48); a(:,57:72)=paradata(:,49:64); [ich,qch]=qpskmod(a,para,nd,ml); %%%%%%%%%%%%%%%%%%%%%插入导频%%%%%%%%%%%%%%%%% [ich,qch]=add_pilot(pilot_symbol,nd,ich,qch); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% kmod=1/sqrt(2); ich=ich.*kmod; qch=qch.*kmod; %%%%%%%%%%%%%%%映射%%%%%%%%%%%%%%%%%%%%%%%%%% [ich1,qch1]=crmapping(ich,qch,fftlen,nd); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% x=ich1+qch1.*i; y=ifft(x); ich2=real(y); qch2=imag(y); %%%%%%%%%%%%%%%%%插入保护间隔%%%%%%%%%%%%%%%%%%%%% fftlen2=fftlen+gilen; [ich4,qch4]=giins(ich2,qch2,fftlen,gilen,nd); tx_data=ich4+qch4*i; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % %%%%%%%%%%%%%上采样和滤波%%%%%%%%%%%%%%%%%%%%%%%%% coeff = [ 0 1 0 -1 0 2 1 -3 -1 3 2 -4 -4 5 6 -6 -9 6 13 -6 -18 5 24 -2 -31 -3 41 11 -53 -25 70 53 -99 -122 160 498 498 160 -122 -99 53 70 -25 -53 11 41 -3 -31 -2 24 5 -18 -6 13 6 -9 -6 6 5 -4 -4 2 3 -1 -3 1 2 0 -1 0 1 0]; % data_up2 = upsample(tx_data,2); data_up2 = zeros(1,2*length(tx_data)); for n=1:length(tx_data) data_up2(1,2*n-1) = tx_data(1,n); end data_filt= conv(data_up2,coeff); data_filt = data_filt(36:end-36); %-- CIC tx_data = cicinterpolator(data_filt,4,1,4); tx_data = reshape(tx_data,1,length(tx_data)); % tx_data = kron(tx_data,ones(1,4)); % f = [0 0.25*(384/512) 0.35*(384/512) 1]; % amp = [1 1 0 0]; % b = remez(80, f, amp); % tx_data = conv(b, tx_data); % tx_data = tx_data(40:end-41); % % ich4 = real(tx_data); % % qch4 = imag(tx_data); %%%%%%%%%%%%%%%%%%%多径信道%%%%%%%%%%%%%%%%%%%%%%% [ich4,qch4] = multi_path(tx_data, delay, amp); ich4 = ich4(1:length(tx_data)); qch4 = qch4(1:length(tx_data)); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% spow=sum(ich4.^2+qch4.^2)/nd./para; attn=0.5*spow*sr/br*10.^(-ebn0/10); attn=sqrt(attn); %%%%%%%%%%%%%%%加入高斯噪声%%%%%%%%%%%%%%%%%%%%%%%% [ich5,qch5]=comb(ich4,qch4,attn); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% rx_data = ich5+i*qch5; %%%%%%%%%%%%%%%%滤波、下采样%%%%%%%%%%%%%%%%%%%%%%% data_cic = cicdecimation(rx_data,4,1,4); coeff = [ 0 1 0 -1 0 2 1 -3 -1 3 2 -4 -4 5 6 -6 -9 6 13 -6 -18 5 24 -2 -31 -3 41 11 -53 -25 70 53 -99 -122 160 498 498 160 -122 -99 53 70 -25 -53 11 41 -3 -31 -2 24 5 -18 -6 13 6 -9 -6 6 5 -4 -4 2 3 -1 -3 1 2 0 -1 0 1 0]; data_filt= conv(data_cic,coeff); data_filt = data_filt(36:end-36); rx_data = downsample(data_filt,2); rx_data = reshape(rx_data,1,length(rx_data)); % rx_data = conv(b,rx_data); % rx_data = rx_data(40:end-41); % rx_data = rx_data(2:4:end); ich5 = real(rx_data); qch5 = imag(rx_data); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%消除保护间隔%%%%%%%%%%%%%%%%%%%%%%%% [ich6,qch6]=girem(ich5,qch5,fftlen2,gilen,nd); rx=ich6+i*qch6; ry=fft(rx); ich7=real(ry); qch7=imag(ry); %%%%%%%%%%%%%%%解映射%%%%%%%%%%%%%%%%%%%%%%%%%%%%% [ich8,qch8]=crdemapping(ich7,qch7,fftlen,nd); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% ich9=ich8./kmod; qch9=qch8./kmod; %%%%%%%%%%%%%%%信道估计%%%%%%%%%%%%%%%%%%%%%%%%% [ich10,qch10]=channel_est(ich9,qch9,pilot_symbol); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% [demodata]=qpskdemod(ich10,qch10,para,nd,ml); %%%%%%%%%%%%%%%%%%%%取出数据%%%%%%%%%%%%%%%%%%%% c=zeros(para,(nd-np)*ml); c(:,1:16)=demodata(:,3:18); c(:,17:32)=demodata(:,21:36); c(:,33:48)=demodata(:,39:54); c(:,49:64)=demodata(:,57:72); demodata0=reshape(c,1,para*(nd-np)*ml); %%%%%%%%%%%%%%%%%%%%%channel decode%%%%%%%%%%%%%%% demodatal0=zeros(1,para*(nd-np)*ml); demodatal=zeros(1,para*(nd-np)); for n=1:(nd-np) demodatal0(1,(n-1)*para*2+1:n*para*2)=inter_sc(demodata0(1,(n-1)*para*2+1:n*para*2),0);%%%%%%%%%解交织%%%%%%%%%%%% demodatal(1,para*(n-1)+1:para*n) = co_dec( demodatal0(1,para*(n-1)*2+1:para*n*2),0 );%%%%%%%%%%卷积码解码%%%%%%% end %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% noe2=sum(abs(demodatal-seridata)); nod2=length(seridata); if noe2~=0 eop=eop+1; else eop=eop; end eop; nop=nop+1; noe=noe+noe2; nod=nod+nod2; end per(l)=eop/nop; ber(l)=noe/nod; end semilogy(k,ber,'b-*'); grid on; xlabel('Eb/N0 (dB)'); ylabel('BER');