dscdma_simulation.rar_CDMA MATLAB 多径_DS-CDMA system_DS-CDMA 误码率_

% Program 5-6 % % Simulation program to realize DS-CDMA system % % dscdma.m % % Programmed by M.Okita and H.Harada % %**************************** Preparation part ***************************** % function ber=ds(b) clear nd=10; % number of symbol ebn0=0:8; % Eb/No user=4; % number of users % %******************** Generation of the spreading code ********************* m=64; code=walsh(m); %************************** Fading initialization ************************** x=randn(1,4); y=randn(1,4); alfa1=x+j.*y; alfa2=x-j.*y; ap=[0,0,-2,-3]; ap=10.^(ap/10); r1=ap.*alfa1; r2=ap.*alfa2; tau=[0,1,3,7]; %**************************** START CALCULATION **************************** for ii=1:length(ebn0) % simulation number of times noe = 0; nod = 0; % while(noe<500) for iii=1:1000 %****************************** Transmitter ******************************** data=rand(user,nd) > 0.5; data1=2*data-1; data2=spread(data1,zeros(size(data1)),code(2:user+1,:)); % spreading if user == 1 % transmission data3=data2; else data3=sum(data2); end %***************************** Fading channel ****************************** % x=randn(1,4); % y=randn(1,4); % alfa1=x+j.*y; % alfa2=x-j.*y; % ap=[0,0,-2,-3]; % ap=10.^(ap/10); % r1=ap.*alfa1; % r2=ap.*alfa2; % tau=[0,1,3,7]; for i=1:length(tau) data4(i,:)=delay1(data3,zeros(size(data3)),length(data3),tau(i)); data5(i,:)=r1(i).*data4(i,:); end data6=sum(data5); %******************************** Receiver ********************************* spow = sum(rot90(data2.^2))/nd; % attenuation Calculation attn = sqrt(0.5*spow*10^(-ebn0(ii)/10)); data7 = comb2(data6,zeros(size(data6)),attn); b=2; for jj=1:user for j0=1:b code0(jj,:)=delay2(code(2+jj-1,:),zeros(1,m),m,tau(j0)); data8(j0,:)=r2(j0).*data7(jj,:); data9(j0,:)=despread(data8(j0,:),zeros(size(data8)),code0(jj,:)); % despreading end if b==1 data10(jj,:)=data9; else data10(jj,:)=sum(data9); end end % data10=despread(data7,zeros(size(data7)),code(2:2+user-1,:)); demodata=data10>0; %************************** Bit Error Rate (BER) *************************** noe2 = sum(sum(abs(data(:,2:nd-1)-demodata(:,2:nd-1)))); nod2 = (nd-2)*user; noe = noe + noe2; nod = nod + nod2; end %******************************** Data file ******************************** ber(ii) = noe / nod; fprintf('%d\t%d\t%d\t%e\n',ebn0(ii),noe,nod,ber(ii)); % fprintf: built in function end %******************************** end of file ******************************** semilogy(ebn0,ber); % 0 1217 32000 3.803125e-002 % 1 1025 32000 3.203125e-002 % 2 781 32000 2.440625e-002 % 3 600 32000 1.875000e-002 % 4 430 32000 1.343750e-002 % 5 280 32000 8.750000e-003 % 6 221 32000 6.906250e-003 % 7 115 32000 3.593750e-003 % 8 54 32000 1.687500e-003