www.gusucode.com > MC-CDMA系统的仿真matlab源码程序 > mc-cdma/blind/NOCP.m
% 清除内存，计时开始 SUI3 信道，先映射后扩频
clear
tic;
%设置参数
totalwords=20;
numusers=4;
wordsize=2;
linktype=0; %上行链路
NumCarr=16;
procgain=16; %扩频码的长度
frameguard=NumCarr; % 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);
H_real=zeros(NumCarr,numusers);
Rxx=[];
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
basesignal0=tranCDMA(Datatx1,procgain,seqnum,linktype);
Data=reshape(basesignal0,NumCarr,length(basesignal0)/NumCarr);
%Find the time waveform using IFFT
BaseSig = ifft(Data); %ifft是对列进行ifft变换。
BaseSignal = reshape(BaseSig,1,size(BaseSig,1)*size(BaseSig,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 0.4 0.9]us，故延迟的抽样为
% 0.4/0.25=1.6,0.9/0.25=3.6，即2和4。
Delay1=[0 0.4+0.1*(k-1) 0.9+0.4*(k-1)];
Delay(k,:)=round(Delay1/0.25);
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,Delay(k,3))];
path12=[zeros(1,Delay(k,2)) path2 zeros(1,Delay(k,3)-Delay(k,2))];
path13=[zeros(1,Delay(k,3)) path3];
RxSignal0=path11+path12+path13;
Rxx(k,:)=RxSignal0(1:length(path1));
h_real(:,k)=[fade(1) zeros(1,Delay(k,2)-1) fade(2) zeros(1,Delay(k,3)-Delay(k,2)-1) fade(3)].';
H_real(:,k)=fft([fade(1) zeros(1,Delay(k,2)-1) fade(2) zeros(1,Delay(k,3)-Delay(k,2)-1) fade(3)].',NumCarr);
end
BER1=zeros(1,7);
BER2=zeros(1,7);
BER3=zeros(1,7);
BERreal=zeros(1,7);
MSE1=zeros(1,7);
MSE2=zeros(1,7);
MSE3=zeros(1,7);
for kk=1:numusers
ber1=[];
ber2=[];
ber3=[];
berreal=[];
mse1=[];
mse2=[];
mse3=[];
for SNR=0:5:30
RxSignal=zeros(1,size(Rxx,2));
for k=1:numusers
RxSignal=RxSignal+awgn(Rxx(k,:),10^(SNR/10),'measured',1234,'linear');
end;
%==================
% RECEIVER SECTION
%==================
% remove cyclic prefix
Rec=reshape(RxSignal,NumCarr,length(RxSignal)/NumCarr);
%=======================================Estimation===============================================
C = walsh(procgain,'+-'); %Find all walsh codes
CC=ifft(C).';%时域扩频码
seqnum=seqnumlist(kk);%取得用户k的扩频码
LL=C(seqnum,:)
Lch=Delay(kk,3);
for i=1:(Lch+1)
Ckk(:,i)=[zeros(1,i-1) LL zeros(1,Lch-(i-1))].';
end;
Ckk0=Ckk(Lch+1:procgain,:);
XX=Rec(Lch+1:NumCarr,:);
[U,S,V]=svd(XX);
minnum=procgain-Lch-numusers;
Snum=min(size(S,1),size(S,2));
UN=U( :,(Snum-minnum+1):Snum);
??hk=inv(UN'*Ckk0);
%计算MSE
mse1=[mse1,mse(abs(hk-h_real(:,kk)))]
%fft变换
Yf=fft(Rec);
HH1=fft(hk,NumCarr);
H1=repmat(HH1,[1 length(RxSignal)/NumCarr]);
Hmse=H_real(:,kk);
H_real11=repmat(H_real(:,kk),[1 length(RxSignal)/NumCarr]);
Rx1=Yf./H1.*abs(H1);
Rxreal=Yf./H_real11.*abs(H_real11);
DemSig1=Rx1(Data_Pattern);
DemSigreal=Rxreal(Data_Pattern);
DemSignal1=reshape(DemSig1,1,size(DemSig1,1)*size(DemSig1,2)); %帧头1估计值
DemSignalreal=reshape(DemSigreal,1,size(DemSigreal,1)*size(DemSigreal,2));%理想估计值
%解扩
seqnum = seqnumlist(kk);
[data10,subsignal1]=recCDMA(DemSignal1,procgain,seqnum,linktype);
[datareal0,subsignalreal]=recCDMA(DemSignalreal,procgain,seqnum,linktype);
%去掉映射
Datarx1=invmapping(subsignal1,mapping,wordsize);
Datarxreal=invmapping(subsignalreal,mapping,wordsize);
%计算误码率
ber10=erruplink(Datatx(kk,:),Datarx1,totalwords);
berreal0=erruplink(Datatx(kk,:),Datarxreal,totalwords);
ber1=[ber1,ber10];
berreal=[berreal,berreal0];
end;
BER1=BER1+ber1;
BERreal=BERreal+berreal;
MSE1=MSE1+mse1;
end;
BER1=BER1./(numusers*totalwords)
BERreal=BERreal./(numusers*totalwords)
MSE1=MSE1/numusers
figure
subplot(2,2,1)
k=0:5:30
semilogy(k,BER1,'-rh')
hold on
semilogy(k,BER2,'-ro')
semilogy(k,BER3,'-rx')
semilogy(k,BERreal,'-.b')
grid on
axis([0 30 10^(-4) 1])
xlabel('SNR/dB'),ylabel('BER')
legend('帧头1','帧头2','平均','理想')
set(gcf,'color',[1 1 1])
set(gca,'xtick',[0:5:30])
subplot(2,2,2)
k=0:5:30
semilogy(k,MSE1,'-rh')
hold on
semilogy(k,MSE2,'-ro')
semilogy(k,MSE3,'-rx')
grid on
axis([0 30 10^(-4) 1])
xlabel('SNR/dB'),ylabel('MSE')
legend('帧头1','帧头2','平均')
set (gcf,'color',[1 1 1])
set(gca,'xtick',[0:5:30])
hold off
toc