Autonomous power control scheme for LTE-advanced macro-femto networks

Substantial capacity gains and enhanced cellular coverage can be achieved by hierarchical deployment of femtocells over existing macrocell networks. However in co-channel deployment scenarios, femtocells can cause severe interference to the neighbouring cells and drive users into outage. Properly selecting femtocell base station transmit power level helps managing the interference, while maintaining femtocells performance. In this paper we propose a downlink power control scheme, which minimizes the transmission power subject to femtocell users´ path loss measurements. However the minimum level of power transmission is set adaptively by the proposed power control algorithm to guarantee the acquired target SINR that could be set according to the considered QoS requirements for the femtocell users. Simulation results show a significant reduction in the outage probability for cell-edge macro users. Moreover, reducing the transmit power level helps to minimize the power consumption, i.e. towards green femtocell networks.