function metric = branch_metric(sig,q_test,ch_coefs)

[n,m] = size(ch_coefs);
[q_dim,foo] = size(q_test);
sig = repmat(sig,q_dim,1);
outsum = 0;
for j=1:m % outer sum
  insum = 0;
 
	for i=1:n % inner sum
      insum1 = ch_coefs(i,j) .* q_test(:,i);
      insum = insum + insum1;
  end
    outsum1 = abs(sig(:,j) - insum) .^ 2;
  outsum = outsum + outsum1;
end
  
metric = outsum;