PAPR Reduction of OFDM Signals Using Cross-Entropy-Based Tone Injection Schemes

This letter considers the use of the tone injection (TI) scheme to reduce the peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) signal. TI is a distortionless technique that can reduce PAPR significantly without data rate loss and does not require the extra side information. However, the optimal TI scheme requires an exhaustive search over all combinations of possible permutations of the expanded constellation, which is a potential problem for practical applications. To reduce the computational complexity while still improving PAPR statistics, this letter first formulates the PAPR reduction with TI scheme as a particular combinatorial optimization problem. Next, it proposes the application of the cross-entropy (CE) method to solve the problem. Computer simulation results show that the proposed CE method obtains the desired PAPR reduction with low computational complexity.