qam16encode_new.m

由4个.m文件组成

%16QAM modulation mapping
%N is the number of output symbol
%qam_sig is the output complex QAM signal vector
%the power of qam_sig is normalized to 1 per symbol.
%qam_bit is the output 4-bit vector
function [qam_sig]=QAM16encode_new(encod1)
N=length(encod1);
lrem=rem(N,4);
if lrem~=0
   encod1(N+1:N+(4-lrem))=0;
end
NN=length(encod1);
   
d=sqrt(40/40);%to normalize the energy of the QAM symbol
%d=1;

ConsI=[-3*d -d d d*3];
ConsQ=[-3*d -d d d*3];
        
I=[1 1;0 1;0 0;1 0];
Q=[1 1;0 1;0 0;1 0];

for i1=0:4:NN-1,
   % encode bit map 
   nu1=[encod1(i1+1) encod1(i1+3)];
   nu2=[encod1(i1+2) encod1(i1+4)];

   for j=1:4
      eu1(j)=(nu1-I(j,:))*(nu1-I(j,:))';
      eu2(j)=(nu2-Q(j,:))*(nu2-Q(j,:))';
   end
   [mineu1,index1]=min(eu1);
   [mineu2,index2]=min(eu2);
 
   qam_sig(i1/4+1)=ConsI(index1)+i*ConsQ(index2);
   end;