Analyses of a class G power amplifier with controlled nonlinear distortion for LTE-signal

Simulations of Computer, Telecommunications and Control Systems
Authors:
Leontiev E.V.
Abstract:

The work considers an analysis of nonlinear distortions in a class G power amplifier and an analysis of an envelope tracking power amplifier with a proposed combined envelope amplifier scheme for LTE cellular base stations. Both considered envelope amplifier schemes feature an additional shaping function to compensate for the AM-AM conversion of the power amplifier, as well as DPD correction for the AM-PM conversion of the amplifier. The analysis results showed that switching between 18 supply voltage levels in the class G power amplifier allows achieving an ACPR characteristic of the output LTE signal at an acceptable level of -50 dBc. Simulation has proved that a standard predistortion technique based on LUT or a Volterra series can be applied to a class G power amplifier at N = 18. The number of supply voltage levels can be reduced to N = 10 using the proposed combined scheme or by applying additional voltage supply filtration of the envelope amplifier.