Adaptive Precoding for Femtocell Interference Mitigation

In this paper 1 , we study interference mitigation in cellular networks with femtocells. We propose to use adaptive distributed beamforming to mitigate downlink interference between the femtocell users, known as Home User Equipments (HUEs), and macrocell users, known as Macrocell User Equipments (MUEs). We propose three beamforming schemes that consider the QoS requirement of the MUE and HUE, respectively, which provide much more flexibility in resource provisioning and signaling requirement. The QoS requirement can be controlled by a threshold that determines the choice of the beamforming weight index. The proposed schemes minimize the interfer-ence at the MUE or maximize the throughput at the HUE depending on the network traffic and QoS constraints. We also analyze the MUE mean throughput by applying order statistics theory.