On the benefits of deliberately introduced baseband nonlinearities in communication systems

In this paper, we propose a baseband nonlinear transformation technique to improve the overall communication system performance, under the peak power constraint. A closed-form expression is derived for the signal-to-noise-and-distortion ratio (SNDR) of certain nonlinear transformations. A strategy for SNR-adaptive optimum clipping is proposed. For orthogonal frequency division multiplexing (OFDM), we show that the optimal clipping ratio leads to an SNDR improvement of 5-7 dB and accompanying decrease in symbol-error-rate. By applying an iterative symbol detection and clipping noise mitigation algorithm at the receiver, we demonstrate that clipping in OFDM can lead to large performance gains.