function x=det_16QAM(I,Q)

% x=det_16QAM(I,Q,modulation)
%
% 16QAM detection
% I,Q :  input symbols
% x : output bit stream
% I,Q,x are column vectors.

i=sqrt(-1);
[m,n]=size(I);
if n~=1
    error('Input vector I should be a column.');
end
[m,n]=size(Q);
if n~=1
    error('Input vector Q should be a column.');
end

scale=sqrt(9/10);
I=I/scale; Q=Q/scale;
x= kron(I<0,[1 0 0 0].') + kron(I>-2/3 & I<2/3,[0 1 0 0].') +  kron(Q<0,[0 0 1 0].') + kron(Q>-2/3 & Q<2/3,[0 0 0 1].');