Contents I. Introduction
The principal drawback of OFDM system performance is the high Peak-to-Average Power Ratio (PAPR). Real power amplifiers have a nonlinear response causing signal compression and clipping that result in signal distortion and adjacent channel interference. Furthermore, broadband PAs introduce memory which gives rise to intersymbol interference (ISI) [1]. Power backoff and PAPR reduction techniques reduce the nonlinear distortion level but do not compensate for the broadband PA memory effects which is necessary for achieving good performance in wireless systems. The PA memory effects can be removed by applying memory predistorter [1], memory precompensation at the transmitter [2], or postcompensation at the receiver [3]. The latter two approaches, which are of interest here, assume that a sufficient power backoff is applied so that the PA memory can be efficiently handled by a frequency-domain equalizer, i.e., any presence of nonlinear distortion is neglected. In addition, the pre- and postcompensation methods rely on a memory model (often FIR model) whose estimation is subject to errors due to, e.g., undermodeling or noise.
