Characterization of optimal resource allocation in cellular networks

Future wireless cellular systems are expected to carry a hybrid traffic including traditional voice transmissions delay-sensitive traffic and high-rate, delay-insensitive data links. In this context there arises the problem of efficient resource allocation, which is optimal with respect to a multi-user QoS (quality of service) functional of interest. This problem statement, opening a wide field of research, is motivated by the point of view of the network operator and differs slightly from the well covered problem of traditional power control achieving specified QoS thresholds. In this work we present a theoretic framework for multi-user QoS optimization in cellular networks. In the context of solvability and ease of obtaining solutions, we state conditions for convexity of the feasible QoS region. We show that under certain requirements regarding the QoS dependence on the SINR (signal to interference and noise ratio) the problem of optimizing the weighted sum of QoS parameters has a unique solution over power vectors representable by a set of matrix equations. We prove that the problem of interest can be made convex and hence even easier tractable. Finally, we compare the optimization of the QoS functional with the common approach of providing maxmin fairness. The presented general framework represents the base for the forthcoming work on algorithmic solutions [4], [5].