PMR-reduction for continuous time OFDM transmit signals by selected mapping

In order to cope with the problems of multipath propagation in communication systems, OFDM is currently the most popular choice amongst digital modulation schemes. The main drawback of OFDM is the high peak-to-average power ratio (PAPR), which PAPR necessitates a highly linear high power amplifier (HPA) in Class-A mode to avoid out-of-band radiation. This kind of amplifiers usually suffers from a bad power efficiency. A recent approach is to deploy different amplifier architectures with potentially higher power efficiencies, such as polar amplifiers. These kinds of amplifiers necessitate signals with low peak-to-minimum power ratio (PMR). In this paper, the PMR of the continuous time transmit signal is analyzed and reduced via Selected Mapping (SLM). To achieve this reduction in the domain of digital signal processing an approximation method for the PMR is derived.