User Association for Ultra Dense Networks with QoS Guarantees

We study the problem of user association in Ultra Dense Networks (UDNs) for two network services; one requiring QoS guarantees to VIP flows, and one best effort service. The goal is to take advantage of statistical multiplexing in order to optimize the use of resources, while ensuring that the VIP flows enjoy active performance guarantees. We formulate this as an optimization problem, show that the problem is convex, and finally demonstrate that the optimum point can in fact be realized by distributed user association rules. In this way, our framework uses the fundamental problem of user association to show that both isolation and statistical multiplexing can be achieved in the context of UDNs, when different services or slices must share BS resources, as envisioned in 5G networks. We demonstrate no violations of the VIP flow constraint on real data traces for mobile network traffic, while a baseline best effort distributed policy applied to this setup inflicts up to 46.5% violations.