Interference-Aware Uplink Power Control in 3GPP LTE-A HetNet

The latest evolution of cellular network, i.e., the heterogeneous network (HetNet) is a promising technique for facing the explosive data demands that the macro-only network can barely meet. However, unplanned small cell deployments, along with an aggressive frequency reuse scheme, generate severe interference between adjacent cells, degrading system performance. In the conventional homogeneous network, fractional power control (FPC), which consists of open-loop power control (OL-PC) and closed-loop power control (CL-PC), is used to determine adequate transmit power of user equipment (UE) to avoid inter-cell interference. However, setting the UE transmit power requires delicate awareness of uplink interference to properly avoid the severe and complicated inter-cell interference in an uplink HetNet environment. In this paper, we propose an interference-aware uplink power control scheme that considers outgoing and incoming interference in each cell in order to fully take the interference situation of the HetNet into account while setting the OL-PC parameter. By using the proposed scheme, uplink interference existing in a HetNet environment can evidently be reduced; therefore, the total cell capacity of both the macro- and the femtocell is increased by 25.6 %. Furthermore, the simulation results of a CL-PC on a 10 ms basis show that the received signal to interference-plus-noise ratio (SINR) of OL-PC with CL-PC is spread less around the target SINR compared to the case of OL-PC alone. Therefore, it is verified that the CL-PC supports the received SINR of OL-PC to meet the target SINR by compensating the channel variation caused by the fading effect.