  At the present time, Wi-Fi networks are everywhere. They operate in
unlicensed radio-frequency spectrum bands (divided in channels), which are
highly congested. The purpose of this paper is to tackle the problem of channel
assignment in Wi-Fi networks. To this end, we have modeled the networks as
multilayer graphs, in a way that frequency channel assignment becomes a graph
coloring problem. For a high number and variety of scenarios, we have solved
the problem with two different automated negotiation techniques: a hill-climber
and a simulated annealer. As an upper bound reference for the performance of
these two techniques, we have also solved the problem using a particle swarm
optimizer. Results show that the annealer negotiator behaves as the best choice
because it is able to obtain even better results than the particle swarm
optimizer in the most complex scenarios under study, with running times one
order of magnitude below. Finally, we study how different properties of the
network layout affect to the performance gain that the annealer is able to
obtain with respect to the particle swarm optimizer.

Networking and Internet Architecture