Before revision:  A necessary condition for the validity of this approach in the asymptotic sense (when the number of wireless nodes tends to infinity) is the existence and uniqueness of a solution to a fixed point equation . However , it was also recently pointed out that this condition is not sufficient;
After revision:  A necessary condition for the validity of this approach in the asymptotic sense (when the number of wireless nodes tends to infinity) is the existence and uniqueness of a solution to a fixed point equation ; however , it was also recently pointed out that this condition is not sufficient;