 combined power of both devices. As the input drive level is reduced, both devices contribute to the output power until a certain point is reached, typically 6 dB below the maximum composite power, where the auxiliary amplifier shuts down and generates no RF power, reducing the DC power consumption. The Doherty amplifier has some disad- vantages. The AM-AM and AM-PM distortion of the amplifier cannot be maintained constant as the auxiliary amplifier turning ON and OFF with the changes of the input power. Therefore DPD method is always used in the Doherty PAs. Furthermore, the per- formance of the Doherty amplifier is very sensitive to the load. As a result, the Doherty amplifier topology is always adopted in the BS PA design. Reconfigurable technique: The reconfigurable technique allows the PA to adapt to dif- ferent configuration in different bands and different modes. With this technique, the load line, bias point, and other configurations can be adjusted. Comparing with wide- band design, this technique will improve the efficiency at specified modes. Digital pre-distortion: This technique can further reduce power consumption. The DPD technology improves both power consumption and linearity. The baseband processing in an NR UE modem has to handle a significantly increased vol- ume of data compared to its LTE counterpart, and this is reflected in increased power con- sumption at the highest data rates. Some early studies have estimated the baseband contribution to UE power consumption at peak throughput, as follows [25]: For UE configuration (2 X 100 MHz, 4X4 DL, 2 X 2 UL), the power at peak through- put for FDD and TDD modes are 4500 and 2970 mW, respectively. For UE configuration (1 X 100 MHz, 4 DL, 2 X 2 UL) the power at peak throughput for FDD and TDD modes are 2250 and 1485 mW, respectively. 726 Chapter 5 That study was based on a very simple set of assumptions. In practice, the baseband proces- sing of two aggregated RF carriers is not exactly twice the power of a single-carrier base- band. More recent stu