Power Consumption and Reduction of High-Power Amplifier in 5G NR Downlink

This article presents a method for estimating the power consumption of radio frequency (RF) power amplifiers (PAs) within the 5G new radio (NR) downlink (from the base station to user equipment), particularly in the absence of user data. We also outline an RF PA design strategy for low power consumption and high efficiency. When no user data signal is transmitted, in the 5G NR downlink, considerably fewer fixed-transmission signals, such as reference signals, are involved compared to 4G long-term evolution (LTE). This results in a reduced operating time for the PA and decreased power consumption. The PA power consumption was calculated by analyzing the signal and nonsignaling periods in a 5G NR downlink without user data. Furthermore, the power consumption is estimated based on measurements obtained from the continuous wave (CW) or the full-buffer signal input/output of a fabricated PA. The fabricated PA is a Doherty amplifier, whose impedance conversion circuit consists of a transmission line connected in parallel to two T-shaped stubs. It can short-circuit the second to the fifth harmonics at the same connection point. The fabricated Doherty amplifier achieved a drain efficiency of 60.2% at a saturated output power of 48.6 dBm at 1852.5 MHz. At a 6 dB back-off from saturation, its drain efficiency was 51.9%. In addition, at a 39.6 dBm modulated signal output, the spurious levels up to the fifth harmonic were −15.8 dBm/MHz or less.