A New LINC Architecture with Efficiency Enhancement for OFDM Signal

In these days, wireless communication requires higher data rate as mobile applications conduct multiple functions. Also, power consumption has become a hot issue in mobile communication research for longer battery life-time. For spectral and power efficiency, orthogonal frequency division multiplexing (OFDM) and linear amplification with nonlinear components (LINC) can be the strongest candidate for a highly efficient communication system [1],[2]. However, there is a trade-off between two properties — linearity and power efficiency, and it is very difficult to satisfy both requirements at the same time. In this work, a new LINC architecture is proposed to enhance the power efficiency without linearity deterioration, especially for OFDM signal. Conventional LINC decomposes input signal S into two phase modulated signals S and S with constant envelope and amplifies them using highly efficient nonlinear amplifiers. After amplification, linearity is restored in combiner where S and S are added. In spite of highly efficient amplification, LINC power efficiency is reduced when the system runs at a low-level input signal. This reduction is dominated when high PAPR signal such as OFDM signal is applied. t ( ) 1 t ( ) 2 t ( )