Decentralized utility maximization in heterogeneous multi-cell scenarios

In this paper we cover the problem of resource allocation in terms of optimum air-interface and cell selection in cellular, heterogeneous multi-air-interface scenarios. For a given set of voice users with minimum quality of service requirements and a set of best effort users we find the optimum allocation that guarantees service for the voice users and maximizes the sum utility of the best effort users. Our model applies for arbitrary heterogeneous scenarios where the air-interfaces belong to the class of interference limited systems like UMTS or to a class with orthogonal resource assignment such as TDMA based GSM or WLAN. We achieve convexity of the problem by a transformation into the domain of mean square errors. Using a dual problem formulation we derive straight forward assignment rules and develop a decentralized algorithm, which solves the optimization problem. Simulation results for a heterogeneous UMTS/GSM scenario show high performance gains of the proposed algorithm compared to a Load Balancing strategy.