A technique originally developed in [4] can be used to compute a(l).
The channel activity of each link l is characterized by an ON/OFF process where the ON period has a duration
of 1 (l) = T(l)s and where the corresponding link is active after an exponentially distributed amount of time with mean 1 g(l) .
The steady-state probability of a set of all links that can be simultaneously active, noted by D, can be expressed in product form by