Green Power Amplification Systems for 3G+ Wireless Communication Infrastructure

This paper presents an overview of system-level solutions for green wireless communication infrastructure. It illustrates that a combination of high efficiency amplification system with a linearity restoration technique is unavoidable. Currently, Doherty power amplifiers along with digital predistortion technique are able to achieve high power efficiency. However, due to the limited bandwidth of digital predistortion systems (typically 20 MHz), feedforward based linearizers which result in significantly lower power efficiency are still considered for wideband solutions (up to 60 MHz). An experimental approach for extending the bandwidth of digital predistortion systems is reported. This setup is then applied for the linearization, using digital predistortion, of a Doherty power amplifier driven by an 8-carrier WCDMA signal having a total bandwidth of 40 MHz.