Green Communications: Digital Predistortion for Wideband RF Power Amplifiers

The RF PA, as one of the most essential components in any wireless system, suffers from inherent nonlinearities. The output of a PA must comply with the linearity requirement specified by the standards. Due to its satisfactory linearization capability, DPD has been widely accepted as one of the fundamental units in modern and future wideband wireless systems. With the help of this flexible digital technology, the inherent linearity problem of PAs operating in the saturation region can be significantly improved, which enables us, the wireless engineers, to create more suitable RF transceiver architectures to provide wireless access with better user experience (linearity perspective) and less power waste (power efficiency perspective). This moves us one more step towards the ultimate green communications. In this article, we discussed the DPD techniques in the context of linearizing nonlinear RF PAs. As the computing-horsepower and the transistor-density of digital IC increases while the cost per transistor decreases, the concept that uses digital enhancement techniques to eliminate active analog imperfects will gain more attention from both industry and academia.