  This paper introduces an efficient method for communication resource use in
dense wireless areas where all nodes must communicate with a common destination
node. The proposed method groups nodes based on their \newt{distance from the
destination} and creates a structured multi-hop configuration in which each
group can relay its neighbor's data. \newt{The large number of active radio
nodes and the common direction of communication toward a single destination are
exploited to reuse the limited spectrum resources in spatially separated
groups}. Spectrum allocation constraints among groups are then embedded in a
joint routing and resource allocation framework to optimize the route and
amount of resources allocated to each node. \newt{The solution to this problem
uses coordination among the lower-layers of the wireless-network protocol stack
to outperform conventional approaches where these layers are decoupled.
Furthermore, the structure of this problem is exploited to obtain} a
semi-distributed optimization algorithm based on the alternating direction
method of multipliers (ADMM) where each node can optimize its resources
independently based on local channel information.
