Energy-Saving Resource Allocation Scheme with QoS Provisioning in OFDMA Femtocell Networks

In this paper, the resource allocation problem is studied in downlink femtocell networks to minimize the energy consumption of femtocell base stations (FBSs), provide delay-aware quality-of-service (QoS) guarantees for femtocell users and limit the cross-tier interference. Specifically, by integrating the concept of effective capacity, users' delay-aware QoS requirements are characterized by the QoS exponent and minimum effective capacity constraints. The problem of minimizing transmit power of FBSs is formulated as a mixed integer programming problem and is decomposed into two subproblems in order to reduce the complexity. Accordingly, a suboptimal subchannel allocation algorithm and a QoS-driven optimal power allocation algorithm are proposed respectively. Simulation results demonstrate that the proposed algorithms can use the lowest transmit power to satisfy diverse delay-aware QoS requirements of femtocell users, which show great advantages in energy saving and QoS provisioning.