Magnitude-Scaled Selected Mapping: A Crest Factor Reduction Scheme for OFDM Without Side-Information Transmission

Selected mapping (SLM) is a distortionless crest factor reduction (CFR) method for orthogonal frequency division multiplexing (OFDM) transmission. With SLM, it is possible to reduce the peak-to-average power ratio (PAR) of an OFDM symbol by several decibels. In this paper, we propose a method for SLM phase sequence detection that does not require side information transmission. We refer to this method as magnitude-scaled SLM, in the sense that it scales the frequency-domain power profile of the OFDM symbol with an envelope function from a set of pre-determined envelope functions. From the envelope of the received symbol, the receiver can detect which envelope and thus which phase sequence was used in the transmission. Also presented in this paper are the theoretical characterizations of the detection error rate (DER) and symbol error rate (SER) in a magnitude-scaled SLM system. Compared with ordinary OFDM without CFR, magnitude-scaled SLM can achieve an order of magnitude SER improvement in a peak-power-limited channel.