Optimization of SNDR in the presence of amplitude limited nonlinearity and multipath fading

Many physical devices, such as power amplifiers, are intrinsically nonlinear and thus introduce nonlinear distortions. Transmission systems with a peak power (or peak amplitude) constraint are considered here. To address the tradeoff between maximizing the output power efficiency and minimizing the signal distortion, we consider two criteria: signal-to-noise-and-distortion ratio and symbol-error-rate. For multipath fading channels, we show that a soft limiter with a particular gain offers an optimal solution when the peak amplitude constraint is imposed at the transmitter. Numerical examples are provided to illustrate the concepts.