Intelligent cell selection satisfying user requirements for inter-system handover in heterogeneous networks

Cell selection for inter-system handover in heterogeneous networks is one of the key issues in 4G cellular networks to maintain constant or near-constant QoS (Quality of Service) where cells may be overloaded. There exist many proposals in literature on cell selection methods for intra-system handovers and inter-system handovers. We propose an intelligent cell selection scheme for inter-system handovers in heterogeneous networks that satisfies user requirements as well as system requirements. The proposed scheme uses uncertain parameters such as user system preference, communication cost, mobile speed, transmission delay, packet loss, and cell loads in the decision process utilizing the aggregation functions in fuzzy set theory. Contrary to many existing schemes which consider only either system parameters or user requirements, the proposed scheme considers both. The proposed scheme hierarchically analyzes the relative value of cell selection parameters based on the current state of heterogeneous networks, the speed of mobile terminals, and the change in QoS. Then, it focuses on the adaptation of relative importance values for each cell selection parameter. Computer simulation results show that our proposed scheme provides systems and users with much better performance compared to existing schemes.