User Association for Spectrum and Service Sharing in Multi-Operator Networks

Inter-operator resource and service sharing, which can utilize the network resources more efficiently and improve users' quality of services, is regarded as a promising method for the operators to construct future multi-operator networks. Particularly, an appropriate user association scheme is quite essential to enhance the network capacity. In this paper, our objective is to maximize the capacity of a multi-operator network by optimizing the user association scheme. Specifically, we investigate three inter-operator sharing scenarios, i.e., service-sharing scenario, spectrum-sharing scenario, and full-sharing scenario. Then, we propose a fractional programming (FP) based algorithm for the user association optimization problem. As inter-operator service sharing enables users to be served by other operators, a sharing coefficient is introduced for each operator to indicate its service level agreement (SLA) for regulating the users' association behaviors. As shown in the simulation results, the user association scheme obtained by the proposed algorithm can achieve a higher capacity than other alternative schemes. In comparison with the scenario without inter-operator sharing, both inter-operator spectrum sharing and service sharing can improve network capacity significantly, and the largest capacity is realized under the full-sharing scenario.