clearclc%=====================================================% common settings%=====================================================ifftsize=256;                                  % equals to number of samples in a useful symbol.numcarr=256;                                   % Number of transmission carrierscp=64;                                         % Guard Interval(length of cyclic extension)=25% of ifftsizeguardtype=2;                                   % 1=zeroed signal; 2=cyclic extension; 3=half zero,half cyclicframeguard=ifftsize+cp;                        % Guard Time between successive frames (one symbol period)wordsize=2;SNRindex=1;numsymb=100;%======================================================%========  SUI-3   ====================================%======================================================order=2005;fade=chanmodel_sui3;                             %fade :3*10000;h11=fade(:,order+1000).';                       %信道參數(三徑信道),時域H11_idea=fft(h11,256);                            %頻域%===============信源==================================  N = 512*numsymb;   % bits  source = randint(1,N);  source = reshape(source,numsymb,512);%=====================================================  for SNR=0:2:20    SNR_dB(SNRindex)=SNR;    numofbiterror_idea=0;         %誤比特率初值設為0；    for kk=1:numsymb    t1 = source(kk,:);    t1 = mapping_ofdm_qpsk(t1);   % Map modulation, QPSK, so 512->256    st1 = ifft(t1);               % Ofdm module, Note: The arrangement of data    st1 = [st1((length(st1)-cp+1):end) st1];   % Add CP    rt1=conv(st1,h11);   % 經過3徑信道    rt1=rt1(1:256+cp);    %rt1 = awgn(rt1,10^(SNR/10),'measured',1234,'linear');    rt1= rt1(cp+1:cp+1+255);    rt1=fft(rt1);       %變換到頻域    %p1_idea=rt1./H11_idea;    p1_idea=rt1;    deofdm1_idea = demapping_ofdm_qpsk(p1_idea); % Demapping    for jj=1:512        if (deofdm1_idea(jj) ~= source(kk,jj))            numofbiterror_idea = numofbiterror_idea+1;        end    end    end   BER1_idea(SNRindex)=numofbiterror_idea/N;   SNRindex=SNRindex+1;  end   semilogy(SNR_dB,BER1_idea,'b-*');   xlabel('SNR')   ylabel('BER')   legend('ideal SUI-3')   grid on   hold off;