turbo码在高斯信道下和衰弱信道下结合qpsk调制的仿真

clear all; %echo file off; % Write display messages to a text file diary QPSK_turbo.txt % Frame size L_total = input(' Please enter the frame size (= info + tail, default: 200) \n'); if isempty(L_total) L_total = 200; % infomation bits plus tail bits end % set code or uncoded with Turbo en_code = input(' set code or uncoded: ( default 0: 0--uncode with Turbo,/1--code with Turbo ) \n'); if isempty(en_code) en_code = 0; end if en_code ==1; % Code generator g = input(' Please enter code generator: ( default: g = [1 1 1; 1 0 1 ] ) \n'); if isempty(g) g = [ 1 1 1; 1 0 1 ]; end %g = [1 1 0 1; 1 1 1 1]; %g = [1 1 1 1 1; 1 0 0 0 1]; [n,K] = size(g); m = K - 1; nstates = 2^m; %puncture = 0, puncturing into rate 1/2; %puncture = 1, no puncturing rate_con = input(' Please choose rate_con (0/1): default 0 \n'); puncture=rate_con; if isempty(puncture) puncture = 0; end % Code rate rate = 1/(2+puncture); else rate =1; end % N_frame N_frame=input(' N_frame = .--default N_frame:100 \n'); if isempty(N_frame) N_frame = 100; % default N_frame end % ferrlim Number of frame errors to count as a stop criterior ferrlimm = input(' Please enter Max number of frame errors to terminate: ferrlimm= default 50 \n '); if isempty(ferrlimm) ferrlimm = 50; end % MaxEbN0db MaxEbN0db = input(' Please putin MaxEbN0db: default 10（db） (-5db ~ **, 2.5 /db per plot) \n'); if isempty(MaxEbN0db) MaxEbN0db = 10; end EbN0db=[-5:2.5:MaxEbN0db]; %产生一组 信噪比的值(db) EbN0db0=EbN0db; %EbN0db0=[5:5:MaxEbN0db]; %产生一组 信噪比的值(db) if en_code==1;% 如果有编码是调整 信噪比 EbN0db0=EbN0db0+5; ferrlim1=ones(1,4).*ferrlimm;% 7 grade for the ferrlim ferrlim2=[1,0.02,0.001]; ferrlim=[ferrlim1,ferrlim2]; else ferrlim=ones(1,7).*ferrlimm;% 7 grade for the ferrlim end %ferrlim=[42,37,27,14,3,0.4,0.005];% 7 grade for the ferrlim %ferrlim=ones(1,7).*ferrlimm;% 7 grade for the ferrlim %mod_channel mod_channel=input(' mod_channel = (0-AWGN/1-Fading).--default 0 \n'); if isempty(mod_channel) mod_channel= 0; % default mod_channel end % Number of Average Average = input(' Please enter number of Average for each frame: default 3 \n'); if isempty(Average) Average = 3; end niter=Average; % en_disp en_disp = input(' Please set the en_disp for the realtime disp figure---default 0-NO/1-YES \n'); if isempty(en_disp) en_disp = 0; end % disp INFO. of the Symtem if en_code ==1; fprintf('\n\n----------------------------------------------------\n'); fprintf(' === SOVA decoder === \n'); fprintf(' Frame size = %6d\n',L_total); fprintf(' code generator: \n'); for i = 1:n for j = 1:K fprintf( '%6d', g(i,j)); end fprintf('\n'); end if puncture==0 fprintf(' code rate = 1/2 \n'); else fprintf(' code rate = 1/3 \n'); end fprintf('\n----------------------------------------------------\n\n'); else fprintf('\n\n----------------------------------------------------\n'); fprintf(' === ONLY QPSK uncoded === \n'); fprintf(' Frame size = %6d\n',L_total); fprintf('\n----------------------------------------------------\n\n'); end err_perfra=zeros(1,N_frame); % 两层循环。外层为信噪比的，内层为仿真的帧数循环 for nEN = 1:length(EbN0db0) en = 10^(EbN0db0(nEN)/10); % 将db的分贝值转换为 对应的 实际值 if nEN ==MaxEbN0db en_disp = 1; else end % 清除 位 错误寄存器和 帧 错误寄存器的值 errs(nEN,1:niter) = zeros(1,niter); %nferr(nEN,1:niter) = zeros(1,niter); nFr = 0; % clear counter of transmitted frames %while ( (err_perfra(nFr) < ferrlim(nEN)) && (nFr < N_frame+1 ) ) while ( nFr < N_frame ) nFr = nFr + 1; %for nFr= 1:N_frame % choose for the bitseq of model if en_code==1 % 下面是turbo码的编码过程 x = round(rand(1, L_total-m)); % info. bits 0 or 1 tra_data = x;% save the transmit datas [temp, alpha] = sort(rand(1,L_total)); % random interleaver mapping en_output = encoderm( x, g, alpha, puncture ) ; % encoder output (+1/-1) bitseq=en_output; else x=randint(1,L_total,[0,1]); % 0 or 1 %产生随机信号 tsmdata=x; bitseq=x; end % 下面是QPSK调制通过信道的解调过程 [S_demod]=mod_demod_QPSK(bitseq,mod_channel,rate,en,en_disp);% S_demode is 0 or 1 rsv_data = S_demod;% save the receive datas if en_code==1;% need the SOVA decode % 下面是turbo码的SOVA译码过程 rec_s = demultiplex(S_demod,alpha,puncture); % demultiplex to get input for decoder 1 and 2 % Initialize extrinsic information L_e(1:L_total) = zeros(1,L_total); for iter = 1:niter %多次求平均 % Decoder one L_a(alpha) = L_e; % a priori info. L_all = sova(rec_s(1,:), g, L_a, 1); % complete info. L_e = L_all - 2*rec_s(1,1:2:2*L_total) - L_a; % extrinsic info. % Decoder two L_a = L_e(alpha); % a priori info. L_all = sova(rec_s(2,:), g, L_a, 2); % complete info. L_e = L_all - 2*rec_s(2,1:2:2*L_total) - L_a; % extrinsic info. % convert to RZ(0/1) RZ_decode(alpha) = (sign(L_all)+1)/2; for al=1:length(RZ_decode) if RZ_decode(al)>0.6 RZ_decode(al)=1; else RZ_decode(al)= 0; end end % caculate the numbers of errors err(iter) = length(find(RZ_decode(1:L_total-m)~=x)); end err_perfra(nFr) = sum(err(1:niter))/niter;%求出 一帧 平均的误码位数 if (err_perfra(nFr) > ferrlim(nEN)) err_perfra(nFr) = ferrlim(nEN); else end % Total number of bit errors for all average of a frame % errs(nEN,1:niter) = errs(nEN,1:niter) + err(1:niter); % Display intermediate results in process fprintf('************** Eb/N0 = %5.2f db **************\n', EbN0db(nEN)); fprintf('Frame size ( contain Bits )= %d, rate 1/%d. \n', L_total, 2+puncture); fprintf('the %d th frame transmitted, %d error in the frame.\n', nFr, err_perfra(nFr)); else % dont need decode of SOVA,ONLY QPSK %for iter = 1:niter %多次求平均 %err_perfra(nFr)=sum(abs(tsmdata-S_demod)); %end % caculate the BER err_perfra(nFr)=sum(abs(tsmdata-S_demod)); %total_BER=total_BER+ num_BER; fprintf('************** Eb/N0 = %5.2f db **************\n', EbN0db(nEN)); fprintf('Frame size ( contain Bits )= %d, rate 1/%d. \n', L_total, rate); fprintf('the %d th frame transmitted, %d error in the frame.\n', nFr, err_perfra(nFr)); end end % 求 N_frame帧 的总错误位数 errs(nEN) = sum(err_perfra(1:nFr)); % Bit error rate BER(nEN) = errs(nEN)/(N_frame*L_total); format long; fprintf('Bit Error Rate :\n'); disp(num2str(BER)); fprintf('\n'); fprintf('***********************************************\n\n'); %save main EbN0db ber BER end figure(3); semilogy(EbN0db,BER,'-*'); xlabel('SNR(dB)') ylabel('BER') legend( 'R= ') title(' Performance of the Turbo QPSK System ') %figure(gcf) %hold on; %figure(3); %semilogy(Eb