Theoretical analysis of the trade-off between efficiency and linearity of the High Power Amplifier in OFDM context

Conference: European Wireless 2012 - 18th European Wireless Conference 2012
04/18/2012 - 04/20/2012 at Poznan, Poland

Proceedings: European Wireless 2012

Pages: 7Language: englishTyp: PDF

Gouba, O. Abel; Louët, Yves (IETR / SUPELEC, Campus de Rennes, Avenue de la Boulaie, CS 47601, 35576 Cesson-Sevigné cedex, France)

Power efficiency and linearity are key parameters of amplification systems but they cannot be achieved simultaneously. A perfect linearity is observed when the power efficiency is low and vice versa. In this paper, we first analyze through some theoretical expressions, the power efficiency and the linearity measured by the Error Vector Magnitude (EVM) metric. Then we propose an analytical trade-off that ensures a good linearity with reasonable efficiency by combining Peak-to-Average Power Ratio (PAPR) reduction and linearization. This analysis is carried out based on Solid State Power Amplifiers (SSPA) and Predistortion (PD) as linearization technique. We show that a trade-off can be achieved for a high distortionless PAPR reduction gain followed by an effective predistortion. Last but not least the most important is to avoid the amplifier saturation by setting the PAPR of the signal after PAPR reduction technique identical to the input back-off (IBO).