Title: Scalable Spectrum Allocation and User Association in Networks with Many Small Cells,
Abstract: A scalable framework is developed to allocate radio resources across a large
number of densely deployed small cells with given traffic statistics on a slow
timescale. Joint user association and spectrum allocation is first formulated
as a convex optimization problem by dividing the spectrum among all possible
transmission patterns of active access points (APs). To improve scalability
with the number of APs, the problem is reformulated using local patterns of
interfering APs. To maintain global consistency among local patterns,
inter-cluster interaction is characterized as hyper-edges in a hyper-graph with
nodes corresponding to neighborhoods of APs. A scalable solution is obtained by
iteratively solving a convex optimization problem for bandwidth allocation with
reduced complexity and constructing a global spectrum allocation using
hyper-graph coloring. Numerical results demonstrate the proposed solution for a
network with 100 APs and several hundred user equipments. For a given quality
of service (QoS), the proposed scheme can increase the network capacity several
fold compared to assigning each user to the strongest AP with full-spectrum
reuse.