PAPR reduction methods based on bit flipping

In this work, two peak-to-average-power ratio (PAPR) reduction methods based on bit flipping are designed for OFDM signals. Rather than sending side information, error correction codes are used to recover the flipped bits, as well as to protect the transmitted data. The first PAPR reduction method combines hard-decision decoding (HDD) and natural mapping. Taking advantage of the fact that the natural mapping symbol is represented as a linear combination of the included bits, the flipping bits can be selected at low complexity. The concept of compressed sensing is introduced in order to minimize the number of flipping bits and retain most of the code distance for error correction. In the second method, a low-density parity-check (LDPC) code is cascaded as an inner code following the HDD code, and Gray mapping is used. Soft-decision decoding (SDD) is applied to the LDPC code, which significantly improves the data protection capability, then the outer HDD code is able to focus on recovering the flipped bits. The designs proposed in this paper show great flexibility and provide a trade-off between PAPR reduction and the error-correction capability.