sync_acquisition_tracking_algo2_dab_receiver_nctu.m

DAB transmitter, synchronization and receiver under development

    elseif ((energy(startpos) < 50000) && mod(nn2,32) > 0)
        Null_start_64=startpos-2;
    else
        Null_start_64=startpos-1;
    end
elseif (energy(2)<threshold && (energy(1)>threshold))
    Null_start_64=startpos-2;
else
    Null_start_64 = 0;
end
    Null_start_64=Null_start_64*32;
    CoarseTimeOffset=Null_start_64;
    energy=[];
    startpos=0;

filter_coeffs_52 = [-0.01150520799654,  0.04662093821552, -0.03077640285271,  -0.0231042241465,  -0.002163312923775,  0.01228271170455,  0.01666390724314,   0.0122309962864,   0.001921130879403,-0.009613726698264, -0.01729442204924, -0.01680913678051,  -0.007257038145782, 0.007988366350245,  0.02198483085216,  0.02680262904334,    0.01759370546702, -0.00420083488149, -0.03021700122233, -0.04715857424595,   -0.04210323639071,-0.008325894095887,  0.05110839485772,   0.1229461387852,     0.1874927531747,   0.2256093150281,   0.2256093150281,   0.1874927531747,     0.1229461387852,  0.05110839485772,-0.008325894095887, -0.04210323639071,  -0.04715857424595, -0.03021700122233, -0.00420083488149,  0.01759370546702,    0.02680262904334,  0.02198483085216, 0.007988366350245,-0.007257038145782,   -0.01680913678051, -0.01729442204924,-0.009613726698264, 0.001921130879403,     0.0122309962864,  0.01666390724314,  0.01228271170455,-0.002163312923775,    -0.0231042241465, -0.03077640285271,  0.04662093821552, -0.01150520799654];
cos_table=[0.8090    0.3090   -0.3090   -0.8090   -1.0000   -0.8090   -0.3090    0.3090    0.8090    1.0000];
sin_table=[0.5878    0.9511    0.9511    0.5878    0.0000   -0.5878   -0.9511   -0.9511   -0.5878   -0.0000];
for kk=1:length(cos_table)
    if cos_table(kk) > 0.9999
        cos_table(kk)=0.9999;
    end
    if sin_table(kk) > 0.9999
        sin_table(kk)=0.9999;
    end
end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%Acquisition Stage Starts%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

sumchk=0; outputmag=0; timing_value=0;         
for toffset_resolv=0:31
    Txr(1,:) = DAB_RX_Frame15(CoarseTimeOffset+1:CoarseTimeOffset+2552*4);
    for t = 1:length(Txr)
        I_stream_2048(1,t) = Txr(1,t);
    end
    t1=1;
    for t = 1:length(Txr)
        I1_stream_2048(1,t) = I_stream_2048(1,t) * cos_table(t1);
        Q1_stream_2048(1,t) = I_stream_2048(1,t) * sin_table(t1);
        if mod(t1,10) == 0
            t1=1;
        else
            t1=t1+1;
        end
    end
%%%%%%%%%%%%%% direct form fir decimation filter start%%%%%%%%%%%%%%%%%%

    y_filter_out_I(1,:) = filter(filter_coeffs_52,1,I1_stream_2048(1,:));
    y_filter_out_Q(1,:) = filter(filter_coeffs_52,1,Q1_stream_2048(1,:));


%%%%%%%%%%%%%% direct form fir decimation filter end %%%%%%%%%%%%%%%%%%
    m=1;
    for ii1=1:length(Txr)/4
        Time_Dom_Symbol_2048_rx_G11_r(1,ii1)=y_filter_out_I(1,m);
        Time_Dom_Symbol_2048_rx_G11_i(1,ii1)=y_filter_out_Q(1,m);
        m=m+4;
    end

    for t=1:length(Time_Dom_Symbol_2048_rx_G11_r)
        Rx(1,t) = complex(Time_Dom_Symbol_2048_rx_G11_r(1,t), -Time_Dom_Symbol_2048_rx_G11_i(1,t));
    end  
    
    Txr1(1,:) = Rx(1,505-toffset_resolv:2048+504-toffset_resolv);
    %%%%%%%%%%%%%Coffset=>coarse frequency offset estimate%%%%%%%%%
    for Coffset=-20:20
        mm=505;
        for i=1:2048
            bb=mm-1;
            temp(i)=exp(j*6.28*(Coffset)*(bb/2048));
            rx_prsC(i)= temp(i) * Txr1(1,i);
            mm=mm+1;
        end  
        rx_prs_2048=fft(rx_prsC(1,:),2048);
        Autocorr11=rx_prs_2048.*conj(phase_ref_beginning);
        output=0;
        for ii=1:2048
            output=Autocorr11(ii)+output;
        end
        outputmag(toffset_resolv+1,Coffset+21)=abs(output);                   
        if sumchk<=outputmag(toffset_resolv+1,Coffset+21)
            sumchk=outputmag(toffset_resolv+1,Coffset+21);
            Cooffset=Coffset;
            timing_value=toffset_resolv;
            output1=0;sumchk1=0;outputmag1=0;
            %%%%%%%%%%%%%f_Cooffset=>fine frequency offset estimate%%%%%%%%%
            for pp=0:24
                Autocorr111=rx_prs_2048.*conj(phase_ref_beginning)*exp(j*2*pi*timing_value*0.04*pp/2048);
                for iii=1:2048
                    output1=Autocorr111(iii)+output1;
                end
                outputmag1(pp+1)=abs(output1);
                if sumchk1<=outputmag1(pp+1)
                    sumchk1=outputmag1(pp+1);
                    f_Cooffset=0.04*pp;
                    metric = [];
                    %%%%%%%%%%%%%fine timing offset estimate%%%%%%%%%
                    for tloop = -200:200
                        pramp = exp(-j*2*pi*tloop*[0:2048-1]/2048)';
                        metric =  [metric sum(abs(sum(reshape(Autocorr111.'.*pramp,64,2048/64))))]; % metric computation
                    end
                    plot([-200:200],metric)
                    xlabel('fine time-offset');ylabel('Metric');
                end
            end
        end
    end
end 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
aad=CoarseTimeOffset+guard_interval*4-timing_value+2048*4;
DAB_RX_Frame17=DAB_RX_Frame15(aad+1-10208:length(DAB_RX_Frame15));


for sym = 1:76
    I_stream_2048_11(sym,:) = DAB_RX_Frame17(1,(sym-1)*10208+1:(sym)*10208);
end

for sym = 1:76
    t1=1;
    for t = 1:length(I_stream_2048_11)
        I1_stream_2048_11(sym,t) = I_stream_2048_11(sym,t) * cos_table(t1);
        Q1_stream_2048_11(sym,t) = I_stream_2048_11(sym,t) * sin_table(t1);
        if mod(t1,10) == 0
            t1=1;
        else
            t1=t1+1;
        end
    end
end
I_stream_2048_11=[];

      %%%%%%%%%%%%%% direct form fir decimation filter start%%%%%%%%%%%%%%%%%%
for sym=1:76
        y_filter_out_I1(sym,:) = filter(filter_coeffs_52,1,I1_stream_2048_11(sym,:));
        y_filter_out_Q1(sym,:) = filter(filter_coeffs_52,1,Q1_stream_2048_11(sym,:));
end

    %%%%%%%%%%%%%% direct form fir decimation filter end %%%%%%%%%%%%%%%%%%
for jj=1:76
        m=1;
        for i=1:length(y_filter_out_I1)/4
            Time_Dom_Symbol_2048_rx_G11_r11(jj,i)=y_filter_out_I1(jj,m);
            Time_Dom_Symbol_2048_rx_G11_i11(jj,i)=y_filter_out_Q1(jj,m);
            m=m+4;
        end
end

for sym=1:76
        for t=1:length(Time_Dom_Symbol_2048_rx_G11_r11)
            Rx_1(sym,t) = complex(Time_Dom_Symbol_2048_rx_G11_r11(sym,t), -Time_Dom_Symbol_2048_rx_G11_i11(sym,t));
        end
end

I1_stream_2048_11=[];
Q1_stream_2048_11=[];

   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   %%%%%%%%%%%%%%%% Coarse Frq Offset + fine frequency offset Compensation
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
aa=Cooffset+f_Cooffset;
for sym=1:76
    for i=1:length(Time_Dom_Symbol_2048_rx_G11_r11)
        bb=i-1;
        temp=exp(j*6.28*aa*(bb/2048));
        Time_Dom_Symbol_2048_rx_G112_track_input(sym,i)= temp * Rx_1(sym,i);
    end
end

   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   %%%%%%%%%%%%%%%% Removal of Guard from the Compensated FIC symbols
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for sym=1:76
    for ii=505:1:2552
        Time_Dom_Symbol_2048_rx113_track_input(sym,(ii-504))=Time_Dom_Symbol_2048_rx_G112_track_input(sym,ii);
    end
end

   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   %%%%%%%%%%%%%%%% OFDM Demodulation
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for sym=1:76
    Time_Dom_Symbol_2048_rx_fft(sym,:) =fft( Time_Dom_Symbol_2048_rx113_track_input(sym,:));
end
Time_Dom_Symbol_2048_rx113_track_input=[];

   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   %%%%%%%%%%%%%%%% Demapping
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for Symbol_count = 1:75
    diff_decoded_buffer(Symbol_count,:)= Time_Dom_Symbol_2048_rx_fft(Symbol_count+1,:)./Time_Dom_Symbol_2048_rx_fft(Symbol_count,:);
    for tt=1:1:1536
        x = freq_deinterleaving_mod1(tt);
        freq_deinterleaved_buffer(Symbol_count,tt) = diff_decoded_buffer(Symbol_count,x);
    end
    for tt=1:1:1536
        if(((real(freq_deinterleaved_buffer(Symbol_count,tt)))>=0) && ((imag(freq_deinterleaved_buffer(Symbol_count,tt)))>=0))
            demapped_buffer(Symbol_count,tt) = 0;

            punctured_output(Symbol_count,tt) = 0;
            punctured_output(Symbol_count,tt+1536) = 0;

        elseif(((real(freq_deinterleaved_buffer(Symbol_count,tt)))>=0) && ((imag(freq_deinterleaved_buffer(Symbol_count,tt)))<0))
            demapped_buffer(Symbol_count,tt) = 1;

            punctured_output(Symbol_count,tt) = 0;
            punctured_output(Symbol_count,tt+1536) = 1;

        elseif(((real(freq_deinterleaved_buffer(Symbol_count,tt)))<0) && ((imag(freq_deinterleaved_buffer(Symbol_count,tt)))>=0))
            demapped_buffer(Symbol_count,tt) = 2;

            punctured_output(Symbol_count,tt) = 1;
            punctured_output(Symbol_count,tt+1536) = 0;

        else
            demapped_buffer(Symbol_count,tt) = 3;

            punctured_output(Symbol_count,tt) = 1;
            punctured_output(Symbol_count,tt+1536) = 1;

        end
    end
end
Time_Dom_Symbol_2048_rx_fft=[];

punctured_output_FIB(1,:) = punctured_output(1,1:2304);
punctured_output_FIB(2,:) = [punctured_output(1,2305:3072),punctured_output(2,1:1536)];
punctured_output_FIB(3,:) = [punctured_output(2,1537:3072),punctured_output(3,1:768)];
punctured_output_FIB(4,:) = punctured_output(3,769:3072);

   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   %%%%%%%%%%%%%%%% Viterbi decoding
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
NO_OF_DATA_BITS  = 768;

decoder_outputFIB(1,:) = Viterbi_decoder_FIC_BER(punctured_output_FIB(1,:),768);
decoder_outputFIB(2,:) = Viterbi_decoder_FIC_BER(punctured_output_FIB(2,:),768);
decoder_outputFIB(3,:) = Viterbi_decoder_FIC_BER(punctured_output_FIB(3,:),768);
decoder_outputFIB(4,:) = Viterbi_decoder_FIC_BER(punctured_output_FIB(4,:),768);

   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   %%%%%%%%%%%%%%%% Descrambling
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for i= 1:1:4
    decoder_output(i,:) = DeScrambler(decoder_outputFIB(i,:),NO_OF_DATA_BITS);
end

crc_rxed_buff = zeros(1,12);            % crc recieved storage buffer.
crc_mismatch_counter = 0;               % crc mismatch counter.
crc_match_counter = 0;
crc_mismatch_flag = 0;

dab_mode=1;        % dummy expression.
if dab_mode==1
    no_of_fibs=3;
elseif dab_mode==2
    no_of_fibs=3;
elseif dab_mode==3
    no_of_fibs=4;
elseif dab_mode==4
    no_of_fibs=6;
end

kk=1;
decoder_output_packed = zeros([1 96*4]);
for i=1:1:NO_OF_DATA_BITS/8
    for j=1:8
        decoder_output_packed(kk) = bitshift( decoder_output_packed(i) , 1 );
        decoder_output_packed(kk) = bitor( decoder_output(1, (i-1)*8 + j ) , decoder_output_packed(kk) );
    end
    kk=kk+1;
end
for i=1:1:NO_OF_DATA_BITS/8
    for j=1:8
        decoder_output_packed(kk) = bitshift( decoder_output_packed(i+96) , 1 );
        decoder_output_packed(kk) = bitor( decoder_output(2, (i-1)*8 + j ) , decoder_output_packed(kk) );
    end
    kk=kk+1;
end
for i=1:1:NO_OF_DATA_BITS/8
    for j=1:8
        decoder_output_packed(kk) = bitshift( decoder_output_packed(i+192) , 1 );
        decoder_output_packed(kk) = bitor( decoder_output(3, (i-1)*8 + j ) , decoder_output_packed(kk) );
    end
    kk=kk+1;
end
for i=1:1:NO_OF_DATA_BITS/8
    for j=1:8
        decoder_output_packed(kk) = bitshift( decoder_output_packed(i+288) , 1 );
        decoder_output_packed(kk) = bitor( decoder_output(4, (i-1)*8 + j ) , decoder_output_packed(kk) );
    end
    kk=kk+1;
end
%___________________EXTRACTION OF  CRC FROM FIB JUST RECEIVED___________________
j=1;
for i=31:32:4*32*no_of_fibs
    crc_rxed_buff(j)=decoder_output_packed(i);     %extracting first higher byte of crc received.
    crc_rxed_buff(j)= bitshift(crc_rxed_buff(j),8);     %left shift buffer by 8 bits.
    i=i+1;                                  % incrementing fic data buffer.
    crc_rxed_buff(j) = bitor(crc_rxed_buff(j),decoder_output_packed(i));
    j=j+1;
end


%_____________________CRC CALCULATION AND COMPARISON__________________________________________________
j=1;
for i=1:32:no_of_fibs*32*4

    temph(j)=crc_calc(i,4*no_of_fibs,decoder_output_packed);
    if crc_rxed_buff(j) == temph(j)     %higher byte crc comparison %comapre the calculated and recived crc
        j=j+1;
        crc_match_counter = crc_match_counter+1;
    else                                              %if crc values doesnt match then increment counter
        j=j+1;
        crc_mismatch_counter = crc_mismatch_counter+1;      % increment the mismatch counter.
        crc_mismatch_flag=1;                              % set crc mismatch flag and abort the process.
        %        break;
    end
    i=i-1;
end
 
clc;
disp('               Output ');
disp('CoarseTimeOffset ');
disp(CoarseTimeOffset);
disp('Fine Time Offset ');  
disp(timing_value);
disp('Coarse Freq Offset ');  
disp(Cooffset);
disp('Fine Freq Offset ');  
disp(outputphase);
disp('No of CRC Mismatch ');  
disp(crc_mismatch);
if crc_mismatch>0
    disp('CRC Check Failed');
else
    disp('CRC Check passed');
end

prog_end = 1;