Novel PAPR Reduction Method for OFDM Signals with Tone Reservation and Index Modulation

This paper introduces a novel method to minimize the peak-to-average power ratio (PAPR) and at the same time enhance the data rates of orthogonal frequency-division multiplexing (OFDM) systems by combining tone reservation (TR) and index modulation (IM). Unlike conventional TR methods, in which a number of tones (or subcarriers) with fixed positions are reserved for canceling the peaks in OFDM signals, the TR-IM method treats the positions of the reserved tones (TR tones) as random and embeds extra information in their positions using IM. In the proposed system, the amplitudes of the TR tones are quantized with a novel quantization method, which not only helps the receiver distinguish between data tones and TR tones, but also enables the TR tones to carry data on their amplitudes. Based on that, we propose a novel forward error correction (FEC) structure to increase the reliability of detection without requiring extra overhead. The proposed FEC design encodes the IM activation pattern rather than the index data bits, and carries the resulting parity bits with a novel mechanism that exploits the extra bits carried on the amplitudes of the TR tones. Simulation results show that, not only does our proposed system have significantly higher data rates, but it can also achieve remarkable PAPR reduction performance as well as a lower bit error rate than the original OFDM systems under the influence of the non-linear distortion caused by power amplifiers.