clippingnhmuc_ssBER.rar_OFDM BER_ber ofdm_phong

clear all tic Nbit = 10240*3*6; %so luong bits--64 QAM thi la 102400*6*2 N = 64; %so kenh--52 doi voi 802.11a N_FFT = 64; %kich co FFT N_data = 64; %so symbol m-ary tren mot OFDM symbol Zeropad = 0; %chen 0 S_temp = []; %tam X = []; %tam X_xen=[]; %tam CR = [1.0 1.2 1.4]; % sigma = 0:1:35; %SNR MM=1:.05:15; %PAPR0 ccdf1=zeros(3,length(MM)); ccdf2=zeros(3,length(MM)); Z = rand(1,Nbit);%tao chuoi bits for i=1:length(Z) if Z(i)>0.5 Z(i)=1; else Z(i)=0; end end Z_backup = Z; m = 64 ; k = log2(m); %dieu che m-ary******************co chinh lai % convert from bit sequences Z to symbol sequences S Z = reshape(Z,k,length(Z)/k); S = zeros(1,size(Z,2)); for a = 1 : size(Z,2) for b = 1 : size(Z,1) S(a) = S(a) + Z(b,a)*2^(b-1); end end Z = Z_backup; S1 = S; %dieu che BPSK S = qammod(S,m); %so symbol du lieu tong cong Nsym = length(S)/N_data;%it bua fai lam tron for jj = 1:length(sigma)%cac muc SNR khac nhau %%%Kenh truyen-AWGN%%%% sigma1 = 10^(-sigma(jj)/10); noise = sqrt(sigma1)*randn(1,length(S))+j*sqrt(sigma1)*randn(1,length(S));%length(X)=length(S) for ii = 1:3%cac muc xen khac nhau %ii=3 X = []; %xoa X cho muc xen khac X_xen = []; %Xoa X_xen cho muc xen khac for jjj = 1:Nsym %Nsymbol symbols OFDM %1 symbol OFDM for i = 1: N_data S_temp(i)= S(i+(jjj-1).*N_data); end %S/P- S_SP = reshape(S_temp,N,length(S_temp)/N); %ifft S_ifft = ifft(S_SP)*sqrt(N_data); %P/S S_PS=reshape(S_ifft,1,length(S_temp)); %Tinh nguong clipping %A(ii) = CR(ii)*sqrt(2)*std(S_PS);%right A(ii) = CR(ii)*sqrt(2)*std(S_PS); %clipping-------don gian nhung gay meo tin hieu for i = 1:length(S_PS) if abs(S_PS(i)) > A(ii) S_PS_xen(i) = A(ii).*exp(j*angle(S_PS(i)));%S_PS(i)/abs(S_PS(i));%xen bien do, pha giu nguyen else S_PS_xen(i) = S_PS(i); end end clear i; %Tinh PAPR cho moi Symbol OFDM trungbinh = S_PS*S_PS'/length(S_PS); dinh = max(S_PS.*conj(S_PS)); paprSymbol(ii,jjj) = dinh/trungbinh; paprSymboldB(ii,jjj) = 10*log10(paprSymbol(ii,jjj)); %tinh PAPR cho moi symbol OFDM_clipping trungbinh = S_PS_xen*S_PS_xen'/length(S_PS_xen);%= mean(S_PS_xen.*conj(S_PS_xen)) dinh = max(S_PS_xen.*conj(S_PS_xen)); paprSymbol_xen(ii,jjj) = dinh/trungbinh; paprSymbol_xendB(ii,jjj) = 10*log10(paprSymbol_xen(ii,jjj)); %tong Nsymbol phat di ne` X = [X S_PS]; %OFDM X_xen = [X_xen S_PS_xen]; %OFDM_xen for iii=1:length(MM); if paprSymboldB(ii,jjj)>MM(iii); ccdf1(ii,iii)=ccdf1(ii,iii)+1; end if paprSymbol_xendB(ii,jjj)>MM(iii); ccdf2(ii,iii)=ccdf2(ii,iii)+1; end end end%end cua jjj %%%%%%%%%%%%%%%%PHIA THU%%%%%%%%%%%%%%%% %Y = X + noise; Y = awgn(X,sigma(jj),'measured'); %Y_xen = X_xen + noise; Y_xen = awgn(X_xen,sigma(jj),'measured'); %%%%%%%%%%%%%%%%OFDM%%%%%%%%%%%%%%%%%%%% %S/P Y_SP = reshape(Y,N,length(Y)/N); %FFT Y_FFT = fft(Y_SP)./sqrt(N_data); %P/S Y_PS = reshape (Y_FFT,1,length(Y)); %M-ary demod Y_thu = qamdemod(Y_PS,m);%*********************co chinh lai %Chuyen tu symbol sequences -> bit sequences Y_thu = de2bi(Y_thu); Y_thu = reshape(Y_thu',1,length(Z)); %figure(5) %stem (abs(Y_thu-Z)) %dem loi dem = 0; lech = abs(Y_thu-Z); for i = 1:length(Z) if lech(i)~=0 dem = dem + 1; end end sobitloi = dem ber(ii,jj) = sobitloi/length(Z) %%%%%%%%%%%OFDM_xen%%%%%%%%%%%%%%%%% %S/P Y_SP_xen = reshape(Y_xen,N,length(Y_xen)/N); %FFT Y_FFT_xen = fft(Y_SP_xen)./sqrt(N_data); %P/S Y_PS_xen = reshape (Y_FFT_xen,1,length(Y_xen)); %M-ary demod Y_thu_xen = qamdemod(Y_PS_xen,m);%*******************co chinh lai %Chuyen tu symbol sequences -> bit sequences Y_thu_xen = de2bi(Y_thu_xen); Y_thu_xen = reshape(Y_thu_xen',1,length(Z)); %dem loi dem = 0; lech_xen = abs(Y_thu_xen-Z); for i = 1:length(Z) if lech_xen(i)~=0 dem = dem+1; end end sobitloi_xen = dem ber_xen(ii,jj) = sobitloi_xen/length(Z) end%end cua ii end%end cua jj %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%CCDF cach khac for ii = 1:3; %ii=1 figure(4) ccdf0(ii,:) = ccdf1(ii,:)./Nsym; ccdf3(ii,:) = ccdf2(ii,:)./Nsym; hold on semilogy(MM,ccdf0(ii,:),'r-') legend('goc ') if ii == 1 semilogy(MM,ccdf3(ii,:),'b-') legend('clipping CL= ') elseif ii == 2 semilogy(MM,ccdf3(ii,:),'g-') legend('clipping CL= ') else semilogy(MM,ccdf3(ii,:),'m-') legend('clipping CL= ') end title('clipping CCDF') xlabel('papr(dB)'),ylabel('ccdf') hold off grid on end ber ber_xen figure(5) semilogy(sigma,ber(1,:),'r-*',sigma,ber_xen(1,:),'b->',sigma,ber_xen(2,:),'g-0',sigma,ber_xen(3,:),'m-+'); grid on end