Amplifier Efficiencies of OFDM Systems with Peak Power and Envelope Variance Reduction

In this paper, we evaluate several dynamic range reduced OFDM systems in terms of power amplifier (PA) efficiency. We point out that when nonlinear amplification is allowed to some extent, as is often the case with practical wireless systems, the distribution of envelope, rather than that of peak-to-average power ratio (PAR), is a more relevant measure. Thus, we focus on the techniques which attempt to flatten the envelope variance such as clipping and filtering and trellis shaping, rather than those reducing a probability of occurrence of high PAR symbols. Numerical results show how much power efficiency savings are achievable by means of these techniques