Complex-Weighted OFDM Transmission with Low PAPR

Abstract

In this paper the novel method of complex weighting for peak-to-average power (PAPR) reduction of OFDM signal is addressed. Combination of different amplitude weighting factors (including rectangular, Bartlett, Gaussian, raised cosine, half-sin, Shannon, and subcarrier masking) with phasing of each OFDM subcarrier using random phase updating algorithm is studied. The impact of complex weighting of OFDM signal on the PAPR reduction is investigated by means of simulation and is compared for the above mentioned weighting factors. Results show that by either amplitude weighting or random phase updating the PAPR can be reduced. Applying both techniques together will further reduce the PAPR For an OFDM system with 32 subcarriers and by Gaussian weighting combined with random phase updating, a PAPR reduction gain of 3.2 dB can be achieved. In order to reduce the complexity, grouping of amplitude weighting and/or phasing is applied. Results show that grouping of amplitudes weighting and phases reduces the hardware complexity while not much impacting the PAPR reduction gain of the method. For even further reduction of the PAPR, complex weighting method with dynamic threshold is investigated. Results show that the PAPR can be further reduced by factor of 4.8 dB.