ons and implementation loss without requiring frequent interactions with the serving gNB. The UE can determine the transmit power based on the transmission parameters sent by the gNB, uplink channel quality, downlink CSI, or the interference knowledge obtained from downlink transmissions. The open-loop power control provides a coarse initial transmit power setting for the device before establishing connection with the base station. It is believed that rate control is more efficient than power control under certain conditions. Rate control in principle implies that the power amplifier is always transmitting at full power and therefore is efficiently utilized. On the other hand, power control often results in inefficient utilization of the power amplifier because the transmission power is often less than its maxi- mum. In practice, the radio-link data rate is controlled by adjusting the modulation scheme and/or the channel coding rate. In good channel conditions, the value of Eb/No at the receiver is high, and the main limitation of the data rate is the bandwidth of the radio link. New Radio Access Physical Layer Aspects (Part 2) 645 In such conditions, use of higher order modulation, for example, 16QAM 64QAM, or 256QAM together with a high coding rate, is more appropriate for link adaptation. Similarly, in the case of poor channel conditions, the use of QPSK and low-rate coding is preferred. Link adaptation by means of rate control is referred to as adaptive modulation and coding. A power control mechanism takes into consideration the serving gNB target link SINR and/ or interference level to other cells/sectors for mitigating inter-cell interference. In order to achieve the target SINR, the serving gNB path loss can be fully or partially compensated based on a trade-off between overall system throughput and cell-edge performance. The UE transmit power is adjusted in order to ensure the level of interference is less than the per- missible interference level. The closed-loop power control, on the other hand, compen