Interference mitigation in two-tier femtocell networks

With the rapid growth of wireless communications, the requirements of the service quality and the data transmission rate are gradually increased. Although the requirements can be met by building more macrocell base stations (MBSs), high implementation costs and other issues are introduced. Hence, the operators can not improve the coverage and service quality easily. However, as the technologies of femtocells are proposed, femtocell access point (FAP) can be installed to solve the problems mentioned above with relatively low equipment expenses and implementation costs. Although femtocells provide many benefits, such as the improvement of indoor signal quality and transmission rate, they also raise some issues, such as cross-tier interference, vertical handoff mechanism, and so on. In this paper, we investigate the problem of cross-tier interference and propose a power control scheme to adjust the transmission power of femtocell UEs to mitigate the cross-tier interference to the MBS in a two-tier femtocell network.