Markku Vainikka

LTE uplink power control and base station antenna down tilt in a 3D channel model

This paper examines the impact of the uplink power control and base station (BS) antenna down tilt on the system level performance in a realistic multicell three dimensional channel model. The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) adopts single carrier frequency division multiple access (SC-FDMA) as an air interface. The intra-cell interference is thus avoided but the inter-cell interference is still an issue. The system level performance depends not only on the transmitted power but also on the inter-cell interference level. Uplink power control scheme is used to limit the mobile station (MS) transmit power in order to reduce the interference. To evaluate the system performance, a realistic propagation environment is essential. We extend the IST WINNER II channel model (WIM II) in the elevation domain and includ the elevation beam pattern. We show mathematical expressions of link loss related to the BS-MS distance, down tilt angle, link loss, beam gain, and the effect of MS open-loop-controlled power. Based on the 3D channel model, the impact of BS antenna down tilt angle effect along with open loop power control scheme is studied.