lookber.m

根据TD-SCDMA系统的特点

close all
clear all
randn('state',sum(100*clock))
  
A=1;
ES=A*A;
Eb=ES;
minTestLength=100000;
maxTestlength=100000000;
index=1;
N=3;
% bpsk modulate
matrix0=(1/sqrt(8))*[1 1;1 exp(i*(N-1)*pi/6);1 exp(i*2*(N-1)*pi/6);1 exp(i*3*(N-1)*pi/6);1 exp(i*4*(N-1)*pi/6);1 exp(i*5*(N-1)*pi/6);1 exp(i*6*(N-1)*pi/6);1 exp(i*7*(N-1)*pi/6)];  
smatrix=diag(exp([i*2*pi/256 i*2*pi*5/256 i*2*pi*16/256 i*2*pi*36/256 i*2*pi*57/256 i*2*pi*105/256 i*2*pi*151/64 i*2*pi*253/256]));
% smatrix=diag(exp([0 i*2*pi/64 i*2*pi*2/64 i*2*pi*3/64 i*2*pi*4/64 i*2*pi*5/64]));% the first design

% matrix2=matrix1';



 for EbN0=0:5:20
N0=10^(-EbN0/10)
noiseRoot=sqrt(N0/2);
errorCount=0;
testCount=0;

length=0;


while(1)
    
% Generate the Rayleigh fading channel 
h0=(randn(1)+j*randn(1))*sqrt(0.5);
h1=(randn(1)+j*randn(1))*sqrt(0.5);
% Noise generate
search=0;
for nn=1:8
n(nn)=(randn(1)+j*randn(1))*noiseRoot;
end


% Soure matrix
 
  % matrix=ones(8,1);
  
% Generate Unitray Matrix 
 
 % S_matrix=diag(exp([i*pi*2/256 i*pi*2*5/256 i*pi*2*16/256 i*pi*2*36/256 i*pi*2*57/256 i*pi*2*105/256 i*pi*2*151/256 i*pi*2*253/256]));
 % 8 rows 1 columns 

 % Transmit source matrix

 src=randint(1,8);
 
 
% src1=2*src;
 number=[128 64 32 16 8 4 2 1]*src';
 % x=A*(2*src-1);
 % max_matrix=zeros(1,4)
 % Transmit matrix
   
    Tmatrix=sqrt(8)*smatrix^number*matrix0;
    Recematrix=zeros(8,2);    
 % Receive matrix
    
      
      Recematrix(:,1)=h0*Tmatrix(:,1)+n';
      Recematrix(:,2)=h1*Tmatrix(:,2)+n';
      m=0;
 % Decision
  for ii=0:255
      
     TR=trace( Recematrix'*(smatrix^ii*matrix0)*(smatrix^ii*matrix0)'*Recematrix);
    % max angle
        if TR>m
         m=TR;
         length=ii;
     end
 end
        
        dst=de2bi(length,8,'left-msb');
        error1=xor(src,dst);
        errorCount=errorCount+sum(error1);
        testCount=testCount+8;

        if(testCount<minTestLength)
            continue;
        end
        tempBER=errorCount/testCount;

         %test if the test length is large enough
        if(tempBER>0)
            thresholdTestLength=100/(tempBER);
        else
            thresholdTestLength=maxTestlength;
        end
        
        %Stop current EbN0 test when the test threshold is reached
        if(testCount>=thresholdTestLength)
            myTestLength(index)=testCount;
            Es=Eb/2;
            myEsN0(index)=10*log10(Es/N0)
            myEbN0(index)=EbN0
            myBER(index)=tempBER
            index=index+1;
            break;
        end
    end
  end

%Draw curves for the results,Eb/N0
figure(1)
semilogy(myEbN0,myBER,'*-');
xlabel('Eb/N0 in dB');
ylabel('bit error rate');
grid 

%Draw curves for the results, Es/N0
% figure(2)
% semilogy(myEsN0,myBER,'+-');
% xlabel('Es/N0 in dB');
% ylabel('bit error rate');
% grid