function dSource = baseMapping(bitSource,baseType)
   simulNUM = length(bitSource);
   switch baseType
       case  1
           dSource = 2*(bitSource-0.5); %BPSK方式調(diào)制到1和－1上
       case 2
           temp = 2*(reshape(bitSource,2,simulNUM/2)-0.5)'; 
           dSource = complex(temp(:,1) ,temp(:,2))/sqrt(2);   % ensure the average symbol power is 1
       case 3
           temp = reshape(bitSource,4,simulNUM/4)';
           x = 2*((0.5-temp(:,1)) .* (3-2*temp(:,3)));
           y = 2*((0.5-temp(:,2)) .* (3-2*temp(:,4)));
           avAmp = (sqrt(2) + sqrt(18) + 2*sqrt(10)) / 4;       % the average signal amplitude
           dSource = complex(x,y)/avAmp;
       otherwise
           error('There is a unsuported Mapping Type'); 
   end