mc_cs_cdma.m

这个是beyong 3G的一个系统仿真程序,它是MC和CDMA的一个结合系统,采用了扩张码的选择.

clc;
display ('%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%')
display ('%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%')
display ('%%%                                                             %%%')
display ('%%%     Conventional MC CS-CDMA system Simulation               %%%')
display ('%%%                                                             %%%')
display ('%%% by: Anvar M. Narzullaev                                     %%%')
display ('%%%     Mobile Communication Lab., Yeungnam University          %%%')
display ('%%%     copyright, 2006                                         %%%')
display ('%%%                                                             %%%')
display ('%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%')
display ('%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%')
clear;
%====================================%
% S Y S T E M   P A R A M E T E R S  %
%====================================%
for cs_bits = [1 2 3 4 5]
para = 60;        % Number of parallel channel
%cs_bits = 1;        % Number of Code selecting bits
fftlen = para/(cs_bits+1); % FFT length
gilen = 0;   % Length of guard interval (points)
ml = 1;             % Modulation Level 1-BPSK
sr   = 256000.0;   % symbol rate
br   = sr * ml;     % bit rate
nd   = 100;          % number of symbol
code_table=((dec2bin((0:(2^cs_bits)-1)')*2)-97);

if cs_bits == 1
    sf = 31;
elseif cs_bits == 2
    sf = 63
elseif cs_bits == 3
    sf = 127
elseif cs_bits == 4
    sf = 255
elseif cs_bits == 5
    sf = 511
end

pn_code = pngen(sf,1);
spr_code = makeset(pn_code,2^cs_bits,sf);
%spr_code = hadamard(sf);

for ebn0 = 0:2:20
    rfade  = 1;                                         % Rayleigh fading 0:nothing 1:consider
    now1   = 2;                                         % number of directwave + delayed wave (2 or 6)
    tstp   = 1 / (sr * para * 511);                               % time resolution
    fd     = 200;                                       % doppler frequency [Hz]
    flat   = 1;                                         % flat Rayleigh environment
    itndel = nd * 300;                              % number of fading counter to skip
    if now1 == 2 %2 path rayleigh fading
        itau   = [0, 2];                                % delay time
        dlvl1  = [0.1, 5.0];                           % attenuation level
        n0     = [6, 7];                                % number of waves to generate fading
        th1    = [0.0, 0.0];                            % initial Phase of delayed wave
        itnd1  = [3001, 4004];                          % set fading counter
    elseif now1 == 6 % 6 path rayleigh fading
        itau   = [0, 1, 2, 3, 4, 5];                   % delay time
        dlvl1  = [0.0, 1.0, 2.0, 3.0, 4.0, 5.0];       % attenuation level
        n0     = [6, 7, 6, 7, 6, 7];                   % number of waves to generate fading
        th1    = [0.0, 0.0, 0.0, 0.0, 0.0, 0.0];       % initial Phase of delayed wave
        itnd1  = [1000, 2000, 3001, 4004, 5005, 6006]; % set fading counter
    end
    nloop=100;  % Number of simulation loops
    noe = 0;    % Number of error data
    nod = 0;    % Number of transmitted data
    for iii = 1:nloop 
        seridata = rand(1,para*nd*ml)>0.5;          % Serial data
        seridata2 = seridata*2-1;                   % BPSK
        paradata = reshape(seridata2, para, nd*ml); % S-to-P convert
        %%===============================================%%
        %%== Select bits for spreading (each 6 bit)      %%
        %%===============================================%%
        m=1;
        for n = cs_bits+1:cs_bits+1:para % select each 6 bits for spreading
            sp_bit(m,:) = paradata(n,:);
            m=m+1;
        end
        %%************************************************%%
        %%== END of Select bits for spreading (each 6 bit)%%
        %%************************************************%%
    
    
        %%===============================================%%
        %%== Spreading Code Selection proccess           %%
        %%===============================================%%
        for n = 1:nd*ml
            l=1;
            for m = 1:cs_bits+1:para
                selected(l,n) = code_select(paradata(m:m+cs_bits-1,n)', code_table, cs_bits);
                l=l+1;
            end
        end
    
        jj = 1;
        for m = 1:ml*nd
                for n = 1:fftlen
                    code(n,jj:jj+sf-1) = spr_code(selected(n,m),:);
                end
            jj=jj+sf;
        end
        %%***********************************************%%
        %%== END of Spreading Code Selection proccess    %%
        %%***********************************************%%
    
    
    
        %%===============================================%%
        %%== Spreading                                   %%
        %%===============================================%%
        jj=1;
        for m=1:ml*nd    
            spread_data(:,jj:jj+sf-1) = ...
                    spread(sp_bit(:,m), code(:,jj:jj+sf-1));
            jj=jj+sf;
        end
        %%***********************************************%%
        %%== END of Spreading                            %%
        %%***********************************************%%
    
    
        %%===============================================%%
        %%== IFFT                                        %%
        %%===============================================%%
        x = ifft(spread_data);
        ich = real(x);
        qch = imag(x);
        %%***********************************************%%
        %%== END of IFFT                                 %%
        %%***********************************************%% 
    
        %%===============================================%%
        %%  Guard Interval insertion & sum all users data%%
        %%===============================================%%
        ll = length(ich);
        fftlen2 = fftlen+gilen; 
        [ich1,qch1] = giins(ich,qch,fftlen,gilen,ll);
        %%***********************************************%%
        %%== END of Guard interval insertion             %%
        %%***********************************************%%  
    
        
        %%***********************************************%%
        %%== Fading channel                              %%
        %%***********************************************%%   
        if rfade == 0
            ich2 = ich1;
            qch2 = qch1;
        else
            [ich2,qch2] = sefade(ich1,qch1,itau,dlvl1,th1,n0,itnd1, ... % fading channel
                                 now1,length(ich1),tstp,fd,flat);
            itnd1 = itnd1 + itndel;
        end
        %%***********************************************%%
        %%== END of Fading channel                       %%
        %%***********************************************%% 
        
    
        %%================ AWGN
        spow = sum(rot90(ich1.^2 + qch1.^2)) / nd/ para; % attenuation Calculation
        attn = sqrt(0.5 * spow * sr / br * 10^(-ebn0/10)); %attenuation calculation
        [ich2, qch2]=comb(ich2,qch2,attn);
        %%================ End of AWGN
    
        %%================ Guard interval removal 
        [ich3,qch3]= girem(ich2,qch2,fftlen2,gilen,ll);
        %%================ Guard interval removal
    
        %%================ FFT
        clear i;
        rx = ich3 + qch3.*i;
        ry = fft(rx);
        ich4=real(ry);
        %%================ End of FFT 
    
        %%===============================================%%
        %%  Correlation (select despread codes)          %%
        %%===============================================%%
            for c = 1:fftlen
                kk=1;
                for n = 1:nd*ml
                    temp(c,n) = 0;
                    s1 = 0;
                    for m = 1:2^cs_bits
                        s2 = abs(sum(ich4(c,kk:kk+sf-1).*spr_code(m,:)));
                        if s2>s1 
                            s1 = s2;
                            temp(c,n) = m;
                        end
                    end
                    kk=kk+sf;
                end
            end
    
            jj = 1;
        for m = 1:ml*nd
                for n = 1:fftlen
                    despread_code(n,jj:jj+sf-1) = spr_code(temp(n,m),:);
                end
            jj=jj+sf;
        end
        %%===============================================%%
        %%  END of Correlation (select despread codes)   %%
        %%===============================================%%
    
    
        %%===============================================%%
        %%== DEspreading                                 %%
        %%===============================================%%
        jj=1;
        for m=1:ml*nd    
            despread_data(:,m) = ...
                    despread(ich4(:,jj:jj+sf-1), despread_code(:,jj:jj+sf-1));
            jj=jj+sf;
        end
        %%***********************************************%%
        %%== END of DEspreading                          %%
        %%***********************************************%%
    
        l=1;
        orig_data = zeros(size(paradata));
        for m = cs_bits+1:cs_bits+1:para
            orig_data(m,:) = despread_data(l,:);
            l=l+1;
        end
    
        l=1;
        for n = 1:nd*ml
            l=1;
            for m = 1:cs_bits+1:para
                orig_data(m:m+cs_bits-1,n) = code_table(temp(l,n),:)';
                l=l+1;
            end
        end
    
        demodata=orig_data>0;
        demodata2 = reshape(demodata,1,para*nd*ml);% P-to-S
    
            %========= BER calc. ==================%   
            for n = 1:length(seridata)
                if seridata(n) ~= demodata2(n)
                    noe = noe + 1;
                end
            end
        %========= end of BER calc. ===========%  
    end
    ber = noe/(nloop*length(seridata));
    fprintf('\n%d\t%e\t%d\n',ebn0,ber,cs_bits);
    if rfade == 0
        fid = fopen('mc_cs_cdma_awgn.dat','a');
        fprintf(fid,'%d\t%e\t%d\n',ebn0,ber,cs_bits); % fprintf: built in function
        fclose(fid);
    end
    if rfade == 1 && now1 == 2
        fid = fopen('mc_cs_cdma_1path.dat','a');
        fprintf(fid,'%d\t%e\t%d\n',ebn0,ber,cs_bits); % fprintf: built in function
        fclose(fid);
    end
    if rfade == 1 && now1 == 6 
        fid = fopen('mc_cs_cdma_6path.dat','a');
        fprintf(fid,'%d\t%e\t%d\n',ebn0,ber,cs_bits); % fprintf: built in function      
        fclose(fid);
    end
end
clear;
end