Linearization of Power Amplifiers Using the Reverse MM-LINC Technique

A new mode-multiplexing linear amplification with nonlinear components (MM-LINC) technique is proposed in this brief. This technique, which is referred to as reverse MM-LINC, consists of using linear amplification with nonlinear components (LINC) hardware, along with two signal decomposition modes, depending on the power of the input signal. This decomposition guarantees acceptable linearity of the signal when the power amplifiers (PAs) are operating at their full power potential. This linearity improvement requires only relatively light computational complexity, which makes this technique a suitable alternative to digital predistortion for mobile and medium-power wireless transmitters. The implementation of the reverse MM-LINC concept for mobile WiMAX applications showed an improvement of 15 dB in the adjacent channel power ratio and a reduction in the error vector magnitude from 10% to 2.2%, when compared with a nonlinearized class-AB PA operating at full power potential. At this operation point, the efficiency of the reverse MM-LINC amplification system was not significantly different from the efficiency of the class-AB PA.