www.gusucode.com > MC-CDMA系统的仿真matlab源码程序 > mc-cdma/sui5/preambletwo.m
% 清除内存，计时开始 SUI5 信道，先映射后扩频
clear
tic;
%设置参数
totalwords=19200;
numusers=4;
wordsize=2;
linktype=0; %下行链路
NumCarr=256;
procgain=32; %扩频码的长度
guardtime=128;
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;
% 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, SUI5
%===============
% 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
% =======================
Delay=[0 4 10]/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(3))];
path12=[zeros(1,Delay(2)) path2 zeros(1,Delay(3)-Delay(2))];
path13=[zeros(1,Delay(3)) path3];
RxSignal0=path11+path12+path13;
RxSignal0=RxSignal0(1:length(path1));
% the ideal channel response
H_real=fft([fade(1) zeros(1,Delay(2)-1) fade(2) zeros(1,Delay(3)-Delay(2)-1) fade(3)].',256);
H_real= H_real([29:229]);
H_real1=repmat(H_real,[1 Numsymb+2]);
ber1=[];
ber2=[];
ber3=[];
berreal=[];
mse1=[];
mse2=[];
mse3=[];
for SNR=0:2:20
RxSignal=awgn(RxSignal0,10^(SNR/10),'measured',1234,'linear');
%==================
% RECEIVER SECTION
%==================
symbwaves=reshape(RxSignal,frameguard,Numsymb+2);% remove cyclic prefix
symbwaves = symbwaves(guardtime+1:frameguard,:); % Strip off the guard interval
Yf=fft(symbwaves);%fft变换
%=======================================Estimation===============================================
%估计导频处的信道频域响应
H_Pilot1=Yf([29:4:125,133:4:229],1)./Data([29:4:125,133:4:229],1);
H_Pilot2=Yf([29:2:127,131:2:229],2)./Data([29:2:127,131:2:229],2);
x1=[1:4:97,105:4:201].';
y1=[1:201]';
H01=INTERP1(x1,H_Pilot1,y1,'linear'); % 帧头1估计值内插
x2=[1:2:99,103:2:201].';
H02=INTERP1(x2,H_Pilot2,y1,'linear'); % 帧头2估计值内插
H03=(H01+H02)/2;% 两个帧头的平均
H1=repmat(H01,[1 Numsymb+2]);
H2=repmat(H02,[1 Numsymb+2]);
H3=repmat(H03,[1 Numsymb+2]);
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.*abs(H1);
Rx2([29:229],:)=Rx2([29:229],:)./H2.*abs(H2);
Rx3([29:229],:)=Rx3([29:229],:)./H3.*abs(H3);
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)); %帧头1估计值
DemSignal2=reshape(DemSig2,1,size(DemSig2,1)*size(DemSig2,2)); %帧头2估计值
DemSignal3=reshape(DemSig3,1,size(DemSig3,1)*size(DemSig3,2)); %平均估计值
DemSignalreal=reshape(DemSigreal,1,size(DemSigreal,1)*size(DemSigreal,2));%理想估计值
%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
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);
% 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(2,2,1)
k=0:2:20
semilogy(k,ber1,'-rh')
hold on
semilogy(k,ber2,'-ro')
semilogy(k,ber3,'-rx')
semilogy(k,berreal,'-.b')
grid on
axis([0 20 10^(-6) 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',[0:4:20])
subplot(2,2,2)
k=0:2:20
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('帧头1','帧头2','平均')
set (gcf,'color',[1 1 1])
set(gca,'xtick',[0:4:20])
hold off
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