PAPR Reduction in OFDM Systems Using Active Constellation Extension and Subcarrier Grouping Techniques

The active constellation extension (ACE) scheme provides an effective means of reducing the peak-to-average power ratio (PAPR) without the need for side information. However, traditional ACE schemes involve a time-consuming iteration process. This letter proposes a novel ACE scheme, along with a low-complexity implementation, for orthogonal frequency division multiplexing (OFDM) systems, where the subcarrier grouping technique is adopted to increase the degrees of freedom in the optimization process. The simulation results show that for an OFDM system with 256 subcarriers and 16-ary quadrature amplitude modulation, the proposed scheme achieves a maximum performance gain of 4.3 dB compared with the original OFDM signal given that Prob(PAPR(x) > γ) = 10
^-3
.