  Heterogeneous wireless networks (HetNets) provide a means to increase network
capacity by introducing small cells and adopting a layered architecture.
HetNets allocate resources flexibly through time sharing and cell range
expansion/contraction allowing a wide range of possible schedulers. In this
paper we define the capacity of a HetNet down link in terms of the maximum
number of downloads per second which can be achieved for a given offered
traffic density. Given this definition we show that the capacity is determined
via the solution to a continuous linear program (LP). If the solution is
smaller than 1 then there is a scheduler such that the number of mobiles in the
network has ergodic properties with finite mean waiting time. If the solution
is greater than 1 then no such scheduler exists. The above results continue to
hold if a more general class of schedulers is considered.
