function[C]=codebook(dimension,size)
realpart1=2*rand(dimension,size)-1;
imagpart1=2*rand(dimension,size)-1;
for i=1:size
    realpart2(:,i)=realpart1(:,i)/norm(realpart1(:,i));
    imagpart2(:,i)=imagpart1(:,i)/norm();
end
C=(realpart2+imagpart2*i)/sqrt(2);