Open-Loop and Closed-Loop Uplink Power Control for LTE System

Uplink power control in Long Term Evolution consists of an open-loop scheme handled by the User Equipment and closed-loop power corrections determined and signaled by the network.Open-loop fractional power control for the user located in the vicinity of the serving eNodeB show high throughput, however,steep performance degradation has been observed when the user is moving towards the cell edge. The user throughput at the cell border can be increased by the closed-loop component. The benefit of closed-loop power control is the higher homogeneity in terms of throughput across the entire network area and the ability to automatically stabilize the network performance under different conditions like cell load and traffic distribution. Simulation results indicate that the LTE power control mechanism is advantageous compared to reference mechanisms using full path loss compensation and SINR balancing. The fractional pathloss compensation can improve the cell-edge bitrate and/or the capacity with up to 20% while at the same time battery life time is improved. Keywords-LTE, uplink, open-loop, closed-loop, power control.