Dynamic cooperative power management algorithm for virtual cell-based femto networks

A large-scale deployment of femto BSs (FBSs) will result in the substantial energy consumption. One fairly intuitive way to improve energy efficiency for femtocells is a sleep mode where the FBS periodically transmits pilot signal especially in low traffic scenario. Nevertheless, it is inefficient when not involved an active call in the FBS coverage area. To address this issue, this paper proposes a dynamic FBS-cooperative power management algorithm (FCPMA) for virtual cell based femto network, where the FBS without the active user can entirely switch off pilot transmissions and the related processing all the time. Based on the proposed scheme, the state transition model is established, and the analytic formulas of energy consumption and average cumulative delay are derived. With the practical LTE system parameters, the numerical simulation and the theoretical analysis match pretty well. Furthermore, the tradeoff relation between energy consumption and average cumulative delay is also showed. The results provide some guidelines for deploying energy efficient femtocell networks.