zhikuo.rar_dsss_zhikuo_zhikuo matlab_直扩_直扩 同步 matlab

% % Simulation program to realize DS-CDMA system % DSCDMA.m % %**************************Preparation part***************************** sr = 256000.0; % symbol rate ml = 2; % number of modulation levels br = sr*ml; % bit rate nd = 100; % number of symbol ebn0 = 3; % Eb/N0 %*************************filter initialization************************* irfn = 21; % number of filter taps IPOINT = 8; % number of oversample alfs=0.5; %roll off factor [xh] =hrollcoef(irfn,IPOINT,sr,alfs,1); %T FILTER [xh2] =hrollcoef(irfn,IPOINT,sr,alfs,0); %R FILTER %************************Spreading code initialization****************** user = 1; % number of users seq=1; %1:M stage = 3; % number of stages ptap1 = [1 3]; % position of taps ptap2 = [2 3]; % regi1 = [1 1 1]; % initial value of register regil2 = [1 1 1]; %*********************** Generation of the spreading code*************** % M-sequence switch seq case 1 code = mseq(stage,ptap1,regi1,user); case 2 m1 = mseq(stage,ptap1,regi1); m2 = mseq(stage,ptap2,regi2); code=goldseq(m1,m2,user); case 3 m1 = mseq(stage,ptap1,regi1); m2 = mseq(stage,ptap2,regi2); code=[goldseq(m1,m2,user),zeros(user,1)]; end code = code*2-1; clen = length(code); %*********************Fading initialization*********% rfade = 0; itau = [0,8]; dlvl1 = [0.0,40.0]; n0 = [6,7]; th1 = [0.0,0.0]; itnd1 = [3001,4004]; now1 = 2; tstp=1/sr/IPOINT/clen; fd = 160; flat = 1; itnde1=nd*IPOINT*clen*30; %*************************START Calculation****************************** nloop = 1000; % simulation number of times noe = 0; nod = 0; for ii=1:nloop %*************************Tranmitter********************************* data = rand(user,nd*ml)>0.5; [ich,qch] = qpskmod(data,user,nd,ml); % QPSK modulation [ich1,qch1] = spread(ich,qch,code); % spreading [ich2,qch2] = compoversamp2(ich1,qch1,IPOINT); [ich3,qch3] = compconv2(ich2,qch2,xh); if user == 1 ich4=ich3; qch4=qch3; else ich4=sum(ich3); qch4=sum(qch3); end %*************fading channel********% if rfade==0 ich5=ich4; qch5=qch4; else [ich5,qch5]=sefade(ich4,qch4,itau,dlvl1,th1,no,itnd1,now1,length(ich4),tstp,fd,flat); itnd1=itnd1+itnde1; end %*********receiver*************% spow=sum(rot90(ich3.^2+qch3.^2))/nd; attn=sqrt(0.5*spow*sr/br*10^(-ebn0/10)); [ich6,qch6]=comb2(ich5,qch5,attn); [ich7,qch7]=compconv2(ich6,qch6,xh2); sampl=irfn*IPOINT+1; ich8=ich7(:,sampl:IPOINT:IPOINT*nd*clen+sampl-1); qch8=qch7(:,sampl:IPOINT:IPOINT*nd*clen+sampl-1); [ich9 qch9]=despread(ich8,qch8,code); demodata=qpskdemod(ich9,qch9,user,nd,ml); %**************bit error rate***********% noe2 = sum(sum(abs(data-demodata))); nod2=user*nd*ml; noe=noe+noe2; nod=nod+nod2; fprintf('%d\t%e\n',ii,noe2/nod2); end %**********data file***********% ber=noe/nod; fprintf('%d\t%d\t%d\t%e\n',ebn0,noe,nod,noe/nod); fid=fopen('BER.dat','a'); fprintf(fid,'%d\t%e\t%f\t%f\t\n',ebn0,noe/nod,noe,nod); fclose(fid);