Multi-Operator Cooperation for Green Cellular Networks with Spatially Separated Base Stations under Dynamic User Associations

This paper presents a cooperation framework for sharing base stations (BSS) among N number of collocated radio-Access networks (RANs) for improving energy efficiency (EE). The proposed framework is equally applicable for collocated and non-collocated BSS belonging to multiple RANs. To the best of our knowledge, this paper is the first for developing such cooperation mechanisms among the spatially separated BSS of N RANs. Independent hard-core Poisson point process (PPP) is used for modeling the locations of BSS with a minimal inter-BS distance, while locations of user equipment devices (UEs) are modeled using PPP. The proposed cooperation mechanisms enable the networks to serve UEs of other RANs allowing some BSS to switch into sleep mode for better EE. Call continuity, signal quality and call blocking limits are guaranteed during this dynamic BS switching. For avoiding high complexity of the generalized EE optimization problem, heuristically guided algorithms with different dynamic UE association policies are proposed. Network performance including fairness of the proposed cooperation under a wide range of system settings is thoroughly investigated. Simulation results clearly demonstrate a substantial improvement in EE as well as an extremely fair cooperation. Comparisons with the other works further validate the proposed framework.