Hybrid BS-Cooperative Power Management Scheme with Self-Organized Sleep Mode in Virtual Cell-Based Femto Networks

A large-scale deployment of femtocell BSs (FBSs) causes substantial energy consumption. This paper proposes a hybrid BS-cooperative power management (HBCPM) scheme with self-organized sleep mode in virtual cell-based femto networks. Firstly, HBCPM builds a leader-member virtual cell framework, in which only one FBS is a FBS leader (FL) and others are FBS members (FMs). Then, the FL acts as an autonomous entity and is responsible for detecting active calls in the virtual cell coverage, while the FMs without active connections can entirely shut down pilot transmissions and the related processing all the time. So it is suited for self-organizing networks (SONs). Based on the proposed scheme, the state transition model is established by the semi-Markov stochastic process, and the analytic formulas of average cumulative delay and interference time as well as the energy consumption are derived. Meanwhile, three prominent-related schemes are also studied by the proposed model. With the practical long-term evolution (LTE) system parameters and three-dimensional femtocell network model, the numerical simulation and theoretical analysis match pretty well, and the tradeoff between the energy consumption and average cumulative delay is also manifested. Moreover, simulation results show that the proposed algorithm outperforms other three schemes in terms of average cumulative interference time and the energy consumption.