if the infinite loop will run 15 times, i would understand that at the end you would have a total of 15 values, where each value is a scalar since you write "value=max(S(:)". In this case, i assume your S is a vector of nx1 and then Value is a scalar.
I would simple define value before the while loop as a vector of size 15 and put a counter that woul update after each iteration
Value=zeros(15,1);
counter=1;
while (1)
if(reply_timer<t)
value(counter)=max(S(:));
end
counter=counter+1;
end
