Crest Factor Reduction for OFDMA Systems

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Crest Factor Reduction for OFDMA Systems [复制链接]

Introduction
Crest factor reduction (CFR) is a technique for reducing the peak-to-average ratio (PAR) of an orthogonal frequency division multiplexing (OFDM) waveform. An OFDM signal is made up in the frequency domain as a set of orthogonal carriers that are each modulated by a constellation symbol. The main disadvantage of OFDM modulation is that the time domain representation approximates a Gaussian distribution and therefore exhibits large envelope variations. Power amplifiers usually only have a limited linear region, making it necessary to back off the amplifier so that the transmit signal never drives the amplifier into the non-linear region, which causes spectral regrowth and inefficient amplifier power.