Layer separability of wireless networks

A general wireless networking problem is formulated to jointly optimize end-to-end user rates, routes, link capacities, transmitted power, frequency and power allocation across subcarriers and fading states. It is proved that wireless networking problems in the presence of fading, while non-convex, have zero Lagrangian duality gap. A consequence of this result is the optimality of separating the problem in (the conventional) layers.