Nonlinear Predistortion of OFDM Signals over Frequency-Selective Fading Channels

The linearization technique known as amplitude and phase (A&P) predistortion, proposed by D'Andrea and Lottici, is applied to the orthogonal frequency-division multiplexing (OFDM) transmission context with nonlinear radio-frequency high-power amplification. The above technique is shown to provide a major enhancement in power efficiency in comparison with the unprotected system, as well as a nonnegligible gain over an alternative linearization strategy, identified as minimum mean-square-error (MMSE) predistortion, presented in the literature for application to OFDM. The relative performance of the A&P and the MMSE predistorter schemes is assessed over the additive white Gaussian noise channel and also in a frequency-selective fading environment. The impact of adjacent channel interference is also discussed.