Self-Organizing Comprehensive Handover Strategy for Multi-Tier LTE-Advanced Heterogeneous Networks

LTE-Advanced was introduced as real 4G with its new features and additional functions, satisfying the growing demands of quality and network coverage for the network operators’ subscribers. The term muti-tier has also being recently used with respect to the heterogeneity of the network by applying the various sub-network cooperative systems and functionalities with self-organizing capabilities. Using indoor short-range low-power cellular base stations e.g. femtocells, in cooperation with existing long-range macrocells are considered as the key technical challenge of this multi-tier configuration. Furthermore shortage of network spectrum is a major concern for network operators which forces them to spend additional attentions to overcome the degradation in performance and quality of services in 4G HetNets. This research investigates handover between the different layers of a heterogeneous LTE-Advanced system, as a critical attribute to plan the best way of interactive coordination within the network for the proposed HetNet. The proposed comprehensive handover algorithm takes multiple factors in both handover sensing and decision stages, based on signal power reception, resource availability and handover optimization, as well as prioritization among macro and femto stations, to obtain maximum signal quality while avoiding unnecessary handovers.