function  [number,complex]=QAM16_demod(c)
%16QAM星座圖重映射---在星座圖上對散亂的點找最近的點作為它的星座點
%complex為離星座點最近的那點的坐標，即是解調后的坐標
%number為解調后的OFDM數據
A=[-3-3*i,-3-i,-1-3*i,-1-i,-3+3*i,-3+i,-1+3*i,-1+i,3-3*i,3-i,1-3*i,1-i,3+3*i,3+i,1+3*i,1+i];
for k=1:16
    B(k)=sqrt((real(c)-real(A(k)))^2+(imag(c)-imag(A(k)))^2);
end
number=find(B==min(B))-1;
complex=A(find(B==min(B)));