Theoretical Results on the Power Efficiency versus Spectral Efficiency Compromise of Wireless Transmitters

摘要

This paper describes some recent theoretical results on the compromise between power efficiency and spectral efficiency that limits the performance of nowadays wireless transmitters. Using only the energy conservation principle, we prove that spectral efficiency, and thus ideal amplitude modulation linearity, can not be achieved in the usual current-mode power amplifier (PA), unless power efficiency is sacrificed. However, we also show that this compromise can be lifted in case of a PA with power supply modulation, as is used in the polar transmitter, and we discuss some of its most important practical implementation challenges.