www.gusucode.com > MC-CDMA系统的仿真matlab源码程序 > mc-cdma/rayleigh(移动信道)/gaijin_yidong.m
% 6径Rayleigh信道,导频数20. %低通滤波器取前一点和后一点 clear tic; %设置参数 totalwords=18000; numusers=4; wordsize=2; linktype=0; %下行链路 ifftsize=256; procgain=16; %扩频码的长度 guardtime=32; guardtype=2; frameguard=ifftsize+guardtime; % Guard Time between successive frames (one symbol period) % 产生要发送的双极性二进制随机数 seed=1234; rand('seed',seed); % Set to new seed seqnumlist = randperm(procgain); Datatx = zeros(numusers,totalwords); basesignal0=zeros(1,totalwords*procgain); for k = 1:numusers, Datatx(k,:)=floor(rand(1,totalwords)*2^wordsize);%产生2^wordsize进制发送数据 %进行映射 mapping=get80216map(2^wordsize); B=Datatx(k,:); for i=1:length(B), Datatx1(i)=mapping(1+B(i)); end; seqnum=seqnumlist(k);%取得用户k的扩频码 %扩频 basesignal_0=tranCDMA(Datatx1,procgain,seqnum,linktype); basesignal0=basesignal0+basesignal_0; %各个用户的扩频信号进行合并 end %ofdm调制 NumCarr =180; %数据载波数 %============= % 每载波要传输多少数据 %============= numsymb = ceil(length(basesignal0)/NumCarr); %如果传输的数据不是数据载波的整数倍,则在后面补零 if length(basesignal0)/NumCarr ~= numsymb, DataPad = zeros(1,numsymb*NumCarr); DataPad(1:length(basesignal0)) = basesignal0; basesignal0 = DataPad; end clear DataPad; %PilotIndex=[45 69 93 117 141 165 189 213]; % pilot interval=24 %生成数据和导频图案 Pilot_number=20; Pattern=ones(ifftsize,numsymb); % the position of data is set as 1. Pattern(129,:)=0; % DC=0 Pattern([1:28,230:256],:)=0; % guard band=0 Pattern([34:10:224],:)=4; % the position of pilot is set as 4. PilotIndex=find(Pattern==4); % the pattern of pilot DataIndex=find(Pattern==1); %the pattern of data %生成导频数据 pilotini=randsrc(length(PilotIndex),1,[1 -1;0.5 0.5])*sqrt(2); %生成数据矩阵 Data=zeros(size(Pattern)); Data(PilotIndex)=pilotini; Data(DataIndex)=basesignal0; %================================== %Find the time waveform using IFFT %================================== BaseSignal = ifft(Data); %ifft是对列进行ifft变换。 %================================= %Add a Guard Period %================================= BaseSignal=[BaseSignal((end-guardtime+1):end,:); BaseSignal]; %BaseSignal = reshape(BaseSignal0,1,size(BaseSignal0,1)*size(BaseSignal0,2)); %先取第一列,再取第二列,…… %=============== % CHANNEL MODEL %=============== fc=3.5e9; V=120; %V km/h fdmax=V*fc/3e8/3.6 %fmax=V*fc/C % channel have delay fade=Rayleigh(fdmax); % fade=Rayleigh_CH2(fdmax); path1=ones(frameguard,1)*fade(1,[1+5000:numsymb+5000]).*BaseSignal; path2=ones(frameguard,1)*fade(2,[1+5000:numsymb+5000]).*BaseSignal; path3=ones(frameguard,1)*fade(3,[1+5000:numsymb+5000]).*BaseSignal; path4=ones(frameguard,1)*fade(4,[1+5000:numsymb+5000]).*BaseSignal; path5=ones(frameguard,1)*fade(5,[1+5000:numsymb+5000]).*BaseSignal; path6=ones(frameguard,1)*fade(6,[1+5000:numsymb+5000]).*BaseSignal; path01=reshape(path1,1,size(path1,1)*size(path1,2)); path02=reshape(path2,1,size(path2,1)*size(path2,2)); path03=reshape(path3,1,size(path3,1)*size(path3,2)); path04=reshape(path4,1,size(path4,1)*size(path4,2)); path05=reshape(path5,1,size(path5,1)*size(path5,2)); path06=reshape(path6,1,size(path6,1)*size(path6,2)); %the delay is [0 0.31 0.71 1.09 1.73 2.51] us path11=[path01 zeros(1,10)]; % the largest delay is 10 sample path12=[zeros(1,1) path02 zeros(1,9)]; path13=[zeros(1,3) path03 zeros(1,7) ]; path14=[zeros(1,4) path04 zeros(1,6)]; path15=[zeros(1,7) path05 zeros(1,3)]; path16=[zeros(1,10) path06]; RxSignal0=path11+path12+path13+path14+path15+path16; RxSignal0=RxSignal0(1:length(path01)); H_real=zeros(ifftsize,numsymb); % the real channel impulse response for k=1:ifftsize H_real(k,:)=H_real(k,:)+fade(1,[1+5000:numsymb+5000])*exp(-j*2*pi*(k-1)*0/ifftsize)+fade(2,[1+5000:numsymb+5000])*exp(-j*2*pi*(k-1)*1/ifftsize)+... fade(3,[1+5000:numsymb+5000])*exp(-j*2*pi*(k-1)*3/ifftsize)+fade(4,[1+5000:numsymb+5000])*exp(-j*2*pi*(k-1)*4/ifftsize)+... fade(5,[1+5000:numsymb+5000])*exp(-j*2*pi*(k-1)*7/ifftsize)+fade(6,[1+5000:numsymb+5000])*exp(-j*2*pi*(k-1)*10/ifftsize); end; H_real1= H_real([29:229],:); ber1=[]; ber2=[]; ber3=[]; berreal=[]; mse1=[]; mse2=[]; mse3=[]; for SNR=0:4:20 RxSignal=awgn(RxSignal0,10^(SNR/10),'measured',1234,'linear'); %================== % RECEIVER SECTION %================== % remove cyclic prefix symbwaves=reshape(RxSignal,frameguard,numsymb); symbwaves = symbwaves(guardtime+1:frameguard,:); % Strip off the guard interval %fft变换 Yf=fft(symbwaves); %提取导频数据 Rec_Pilot=Yf(PilotIndex); %估计导频处的信道频域响应 H_Pilot=Rec_Pilot./pilotini; H_Pilot=reshape(H_Pilot,Pilot_number,numsymb); Gp=fft(H_Pilot,Pilot_number); Gp1=Gp(1,:); Gp2=Gp(Pilot_number,:); Gp3=zeros(201,numsymb); Gp3(1,:)=Gp1; Gp3(201,:)=Gp2; H=ifft(Gp3,201);%改进前 %aa=abs(Gp); %aa1=aa(2:(Pilot_number-1),:);%18*160 %bb=sum(aa1)/(Pilot_number-2);%均值 %bb1=repmat(bb,[(Pilot_number-2) 1]);%18*160 %cc=sum((aa1-bb1).^2)/(Pilot_number-2); cc=var(Gp(2:(Pilot_number-1),:));%1*160 delta=sqrt(cc/(Pilot_number-2));%1*160 Gp10=Gp1-delta; Gp20=Gp2-delta; Gp30=zeros(201,numsymb); Gp30(1,:)=Gp10; Gp30(201,:)=Gp20; H0=ifft(Gp30,201);%改进后 %ls估计 X=6:10:196; XI=1:201; H_ls=INTERP1(X,H_Pilot,XI,'linear','extrap'); %计算mse esterr1=H_ls-H_real1; % LS estimation error esterr2=H-H_real1; esterr3=H0-H_real1; mse1=[mse1,mse(abs(esterr1))] % Mean Square Error of LS estimation mse2=[mse2,mse(abs(esterr2))] % Mean Square Error of LMMSE estimation mse3=[mse3,mse(abs(esterr3))] Rx1=Yf; Rx2=Yf; Rx3=Yf; Rxreal=Yf; Rx1([29:229],:)=Rx1([29:229],:)./H_ls; Rx2([29:229],:)=Rx2([29:229],:)./H; Rx3([29:229],:)=Rx3([29:229],:)./H0; Rxreal([29:229],:)=Rxreal([29:229],:)./H_real1; DemSig1=Rx1(DataIndex); DemSig2=Rx2(DataIndex); DemSig3=Rx3(DataIndex); DemSigreal=Rxreal(DataIndex); DemSignal1=reshape(DemSig1,1,size(DemSig1,1)*size(DemSig1,2)); % complex signal to be de demapped DemSignal2=reshape(DemSig2,1,size(DemSig2,1)*size(DemSig2,2)); DemSignal3=reshape(DemSig3,1,size(DemSig3,1)*size(DemSig3,2)); DemSignalreal=reshape(DemSigreal,1,size(DemSigreal,1)*size(DemSigreal,2)); %解扩 subsignal1=[]; subsignal2=[]; subsignal3=[]; subsignalreal=[]; for k=1:numusers seqnum = seqnumlist(k); [datarx1, subsignal10] = reccdma(DemSignal1,procgain,seqnum,linktype); subsignal1=[subsignal1;subsignal10]; [datarx2, subsignal20] = reccdma(DemSignal2,procgain,seqnum,linktype); subsignal2=[subsignal2;subsignal20]; [datarx3, subsignal30] = reccdma(DemSignal3,procgain,seqnum,linktype); subsignal3=[subsignal3;subsignal30]; [datarxreal, subsignalreal0]=reccdma(DemSignalreal,procgain,seqnum,linktype); subsignalreal=[subsignalreal;subsignalreal0]; end; %去掉映射 Datarx1=invmapping(subsignal1,mapping,wordsize); Datarx2=invmapping(subsignal2,mapping,wordsize); Datarx3=invmapping(subsignal3,mapping,wordsize); Datarxreal=invmapping(subsignalreal,mapping,wordsize); %计算误码率 ber10=err(Datatx,Datarx1,totalwords,numusers); ber20=err(Datatx,Datarx2,totalwords,numusers); ber30=err(Datatx,Datarx3,totalwords,numusers); berreal0=err(Datatx,Datarxreal,totalwords,numusers); ber1=[ber1,ber10] ber2=[ber2,ber20] ber3=[ber3,ber30] berreal=[berreal,berreal0] end figure subplot(1,2,1) k=0:4:20 semilogy(k,ber1,'-r*') hold on semilogy(k,ber2,'-rs') semilogy(k,ber3,'-bx') semilogy(k,berreal,'-.b') grid on axis([0 20 10^(-4) 0.5]) xlabel('SNR/dB'),ylabel('BER') legend('LS','变换域','改进后','理想') set (gcf,'color',[1 1 1]) set(gca,'xtick',[0:4:20]) hold off subplot(1,2,2) k=0:4:20 semilogy(k,mse1,'-r*') hold on semilogy(k,mse2,'-rs') semilogy(k,mse3,'-ro') grid on axis([0 20 10^(-4) 1]) xlabel('SNR/dB'),ylabel('MSE') legend('LS','变换域','改进后') set (gcf,'color',[1 1 1]) set(gca,'xtick',[0:4:20]) hold off toc