Amplifier efficiency and distortion trade-off of OFDM system with iterative clipping and filtering

Due to the growing concerns toward green communications, future wireless communications systems should aim at higher data rate with even lower power consumption. Since the power amplifier (PA) is a major power consuming analog component, its efficient use is of primary concern in such green communications framework. Orthogonal frequency division multiplexing (OFDM) is a standard approach for achieving high data rate communications with high reliability, but one of its well-known drawbacks is low PA efficiency caused by its signal with high peak-to-average power ratio (PAPR). The use of iterative clipping and filter (ICF) has been widely studied to reduce peak-to-average ratio (PAPR) so that sufficient usage of PA is achieved, but at a cost of in-band distortion and increasing complexity at the transmitter. In many communication standards, however, there is a constraint in acceptable in-band distortion level and thus the question is how much improvement can one achieve in terms of PA efficiency for a given in-band distortion constraint. In this paper, we investigate the trade-off between amplifier efficiency and distortion for an OFDM system operated with ICF in the long term evolution (LTE) framework, and reveal its limitation when considering the effect of PA that comes after the ICF in a practical circuit.