function [x]=layerMappingForSpatialMultiplexingTwoCodeWords(numberOfLayers,d0,d1)%layer mapping for spatial multiplexing two code words
% d0=[1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16]
% d1=[1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16]
% select=2
if numberOfLayers==2 select=0;
   elseif numberOfLayers==3 select=1;
           else numberOfLayers==4; select=2 ;
end
end
  switch select;
    case 0,
        x0=zeros(1,length(d0));
        x1=zeros(1,length(d1));
        x=zeros(length(d0)+length(d1),1);
        x0=d0;
        x1=d1;
        x=[x0,x1].';
    case 1,
        x0=zeros(1,length(d0));
        x1=zeros(1,length(d1)/2);
        x2=zeros(1,length(d1)/2);
        x0=d0;
        x1=d1(1:2:end);
        x2=d1(2:2:end);
        x=[x0,x1,x2].';
    case 2,
        x0=zeros(1,length(d0)/2);
        x1=zeros(1,length(d0)/2);
        x2=zeros(1,length(d1)/2);
        x3=zeros(1,length(d1)/2);
        x0=d0(1:2:end);
        x1=d0(2:2:end);
        x2=d1(1:2:end);
        x3=d1(2:2:end);
        x=[x0;x1;x2;x3].';
end
end