www.gusucode.com > MC-CDMA系统的仿真matlab源码程序 > mc-cdma/sui5/preamble1LS_LMMSE_ML.m
% 清除内存,计时开始 SUI3 信道 clear tic; %设置参数 totalwords=19200; numusers=4; wordsize=2; linktype=0; %下行链路 NumCarr=256; procgain=16; %扩频码的长度 guardtime=64; guardtype=2; frameguard=NumCarr+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 Tx=dec2bin(Datatx.',wordsize)-48; %ofdm调制 %============= % 每载波要传输多少数据 %============= Numsymb = ceil(length(basesignal0)/192); %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)/192 ~= Numsymb, DataPad = zeros(1,Numsymb*192); DataPad(1:length(basesignal0)) = basesignal0; basesignal0 = DataPad; end clear DataPad; %生成数据和导频图案 Pattern=ones(NumCarr,Numsymb+2); % the position of data is set as 1. Pattern(129,:)=0; % DC=0 Pattern([1:28,230:256],:)=0; % guard band=0 Pattern([45:24:213],:)=4;% the position of pilot is set as 4. Pattern(:,[1,2])=0; Data_Pattern=find(Pattern==1); %the pattern of data %生成数据矩阵 w=round(rand(1,Numsymb)); % generate Wk Data=zeros(size(Pattern)); for n=3:Numsymb Data([45,93,189,213],n)=1-2*w(n); % [-84,-36,60,84]=1-2W Data([69,117,141,165],n)=2*w(n)-1; % [-60,-12,12,36]=1-2W' end Data(Data_Pattern)=basesignal0; %插入用户数据 % 插入帧头 Data([29:229],1)=2*[1+j,0,0,0,1+j,0,0,0,1+j,0,0,0,1-j,0,0,0,-1+j,0,0,0,1+j,0,0,0,1+j,0,0,0,1+j,0,0,0,1-j,0,0,0,-1+j,0,0,0,1+j,0,0,0,1+j,0,0,0,1+j,0,0,0,1-j,0,0,0,-1+j,0,0,0,1-j,0,0,0,1-j,0,0,0,1-j,0,0,0,-1-j,0,0,0,1+j,... 0,0,0,-1+j,0,0,0,-1+j,0,0,0,-1+j,0,0,0,1+j,0,0,0,-1-j,0,0,0,0,0,0,0,-1-j,0,0,0,1-j,0,0,0,1+j,0,0,0,-1-j,0,0,0,-1+j,0,0,0,1-j,0,0,0,1+j,0,0,0,-1+j,0,0,0,1-j,0,0,0,-1-j,0,0,0,1+j,0,0,0,-1+j,0,0,0,-1-j,0,0,0,1+j,0,0,0,1-j,0,0,0,-1-j,0,0,0,1-j,0,0,0,1+j,0,0,0,-1-j,0,0,0,-1+j,0,0,0,-1+j,0,0,0,-1-j,0,0,0,1-j,0,0,0,-1+j,0,0,0,1+j]'; Data([29:229],2)=2*[1,0,-1,0,-1,0,-1,0,1,0,1,0,1,0,1,0,-1,0,1,0,-1,0,-1,0,-1,0,1,0,-1,0,1,0,1,0,1,0,1,0,-1,0,1,0,1,0,1,0,-1,0,1,0,-1,0,1,0,1,0,-1,0,-1,0,1,0,-1,0,1,0,-1,0,1,0,1,0,-1,0,1,0,1,0,-1,0,-1,0,-1,0,1,0,-1,0,-1,0,-1,0,-1,0,-1,0,1,0,1,0,0,0,1,0,-1,0,-1,0,1,0,-1,0,1,0,1,0,1,0,1,0,-1,0,1,0,1,0,1,0,1,0,-1,0,1,0,-1,0,-1,0,-1,0,-1,0,1,0,1,0,-1,0,1,0,-1,0,-1,0,-1,0,-1,0,-1,0,-1,0,-1,0,-1,0,1,0,1,0,1,0,-1,0,-1,0,-1,0,1,0,1,0,-1,0,-1,0,-1,0,1,0,-1,0,-1,0,1,0,-1,0,-1,0,-1]'; %================================== %Find the time waveform using IFFT %================================== BaseSignal = ifft(Data); %ifft是对列进行ifft变换。 %================================= %Add a Guard Period %================================= BaseSignal0=[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, channel have delay %=============== % generate channel parameter which is unknown to receiver % 抽样频率f=4MHz,周期0.25us,信道延迟Delay=[0 4 10]us,故延迟的抽样为 % 4/0.25=16,10/0.25=40,即16和40。 % SUI-5 channel % ======================= P = [0 -5 -10]; %db P = 10.^(P/10); % calculate linear power K=[1 0 0]; s2=P./(K+1); m2=P.*(K./(K+1)); fade1=sqrt(s2)*sqrt(1/2)*(1+j); fade2=m2; fade=fade1+fade2; path1=BaseSignal*fade(1); path2=BaseSignal*fade(2); path3=BaseSignal*fade(3); path11=[path1 zeros(1,40)]; path12=[zeros(1,16) path2 zeros(1,24)]; path13=[zeros(1,40) path3]; RxSignal0=path11+path12+path13; RxSignal0=RxSignal0(1:length(path1)); H_real=fft([fade(1) zeros(1,15) fade(2) zeros(1,23) fade(3)].',256); H_real= H_real([29:229]); H_real1=repmat(H_real,[1 Numsymb+2]); ber1=[]; ber2=[]; ber3=[]; berreal=[]; mse1=[]; mse2=[]; mse3=[]; %LMMSE 参数设置 switch wordsize case 2 beita=1; % beita=E{|Ck|^2}*E{1/|Ck}^2}=constant case 4 beita=17/9; % beita=17/9 for 16-QAM , and beita=1 for QPSK case 6 beita=2.6854; % beita=2.6854 for 64-QAM otherwise error('error mapping type!') end L=40; ratio=L/NumCarr; for ri=1:256 %相关函数 for ci=1:256 if ri==ci Rhh(ri,ci)=1; else Rhh(ri,ci)=(1-exp(-j*2*pi*ratio*(ri-ci)))/(j*2*pi*ratio*(ri-ci)); % attention !!! end end end for SNR=0:4:20 RxSignal=awgn(RxSignal0,10^(SNR/10),'measured',1234,'linear'); %================== % RECEIVER SECTION %================== % remove cyclic prefix symbwaves=reshape(RxSignal,frameguard,Numsymb+2); symbwaves = symbwaves(guardtime+1:frameguard,:); % Strip off the guard interval %fft变换 Yf=fft(symbwaves); %=======================================Estimation=============================================== %估计导频处的信道频域响应 %LS H_Pilot2=Yf([29:2:127,131:2:229],2)./Data([29:2:127,131:2:229],2); x2=[1:2:99,103:2:201].'; y1=[1:201]'; H01=INTERP1(x2,H_Pilot2,y1,'linear'); % 帧头2估计值内插%时域估计 %LMMSE C=beita/10^(SNR/10); % constant coefficient M=[29:229]; N=[29:2:127,131:2:229]; Rpp=Rhh(N,N); Rhp=Rhh(M,N); Wt=Rhp*inv(Rpp+C*eye(length(N))); % weight matrix of LMMSE estimation H02=Wt*H_Pilot2; %ML Nc=256; n=(0:Nc-1)'; k=0:Nc-1; F=1/sqrt(Nc)*exp(-j*2*pi*n*k/Nc); % generate an Nc by Nc unitary FFT matrix, satisfy:F'=inv(F) Nh=41; Fhh=F(M,1:Nh); Fuh=F(N,1:Nh); H03=Fhh*pinv(Fuh)*H_Pilot2; H1=repmat(H01,[1 Numsymb+2]); H2=repmat(H02,[1 Numsymb+2]); H3=repmat(H03,[1 Numsymb+2]); H10=abs(H1); H20=abs(H2); H30=abs(H3); mse1=[mse1,mse(abs(H_real-H01))] mse2=[mse2,mse(abs(H_real-H02))] mse3=[mse3,mse(abs(H_real-H03))] Rx1=Yf; Rx2=Yf; Rx3=Yf; Rxreal=Yf; Rx1([29:229],:)=Rx1([29:229],:)./H1.*H10; Rx2([29:229],:)=Rx2([29:229],:)./H2.*H20; Rx3([29:229],:)=Rx3([29:229],:)./H3.*H30; Rxreal([29:229],:)=Rxreal([29:229],:)./H_real1.*abs(H_real1); DemSig1=Rx1(Data_Pattern); DemSig2=Rx2(Data_Pattern); DemSig3=Rx3(Data_Pattern); DemSigreal=Rxreal(Data_Pattern); DemSignal1=reshape(DemSig1,1,size(DemSig1,1)*size(DemSig1,2)); % LS DemSignal2=reshape(DemSig2,1,size(DemSig2,1)*size(DemSig2,2)); %MMSE DemSignal3=reshape(DemSig3,1,size(DemSig3,1)*size(DemSig3,2)); %ML DemSignalreal=reshape(DemSigreal,1,size(DemSigreal,1)*size(DemSigreal,2)); %理想 %解扩 subsignal1=[]; subsignal2=[]; subsignal3=[]; subsignalreal=[]; for k=1:numusers seqnum = seqnumlist(k); [data10,subsignal10]=recCDMA(DemSignal1,procgain,seqnum,linktype); subsignal1=[subsignal1;subsignal10]; [data20,subsignal20]=recCDMA(DemSignal2,procgain,seqnum,linktype); subsignal2=[subsignal2;subsignal20]; [data30,subsignal30]=recCDMA(DemSignal3,procgain,seqnum,linktype); subsignal3=[subsignal3;subsignal30]; [datareal0,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 %计算误码率 Rx10=dec2bin(Datarx1)-48; ber10=sum(sum(xor(Tx,Rx10)))/(length(Data_Pattern)*wordsize); Rx20=dec2bin(Datarx2)-48; ber20=sum(sum(xor(Tx,Rx20)))/(length(Data_Pattern)*wordsize); Rx30=dec2bin(Datarx3)-48; ber30=sum(sum(xor(Tx,Rx30)))/(length(Data_Pattern)*wordsize); Rx40=dec2bin(Datarxreal)-48; berreal0=sum(sum(xor(Tx,Rx40)))/(length(Data_Pattern)*wordsize); ber1=[ber1,ber10] ber2=[ber2,ber20] ber3=[ber3,ber30] berreal=[berreal,berreal0] end figure subplot(2,2,1) k=0:4:20 semilogy(k,ber1,'-rh') hold on semilogy(k,ber2,'-ro') semilogy(k,ber3,'-rx') semilogy(k,berreal,'-.b') grid on axis([0 20 10^(-4) 0.5]) xlabel('SNR/dB'),ylabel('BER') legend('LS','LMMSE','ML','理想') set (gcf,'color',[1 1 1]) set(gca,'xtick',[0:4:20]) hold off subplot(2,2,2) k=0:4:20 semilogy(k,mse1,'-rh') hold on semilogy(k,mse2,'-ro') semilogy(k,mse3,'-rx') grid on axis([0 20 10^(-4) 1]) xlabel('SNR/dB'),ylabel('MSE') legend('LS','LMMSE','ML') set (gcf,'color',[1 1 1]) set(gca,'xtick',[0:4:20]) hold off toc