My advice would be not to vectorize it completely (although there are ways to do so), but rather reduce it to one loop as below.
[m,n]=size(Sxx);
k=1:round(m/2);
SxxConj=conj(Sxx(:,1:n-1));
T=nan(n-1);
for i=1:n-1
B=ifft(Sxx(:,i).*SxxConj, [],1,'symmetric'); %If <R2016b use bsxfun
[~,T(i,:)]=max(B(k,:),[],1); %EDITED
end
You could also convert this to a parfor loop if the serial performance is insufficient.
