Invertible Subset LDPC Code for PAPR Reduction in OFDM Systems with Low Complexity

In this paper, we introduce a new family of low-density parity-check (LDPC) codes, called as invertible subset LDPC (IS-LDPC) code, for peak-to-average power ratio (PAPR) reduction in OFDM systems with low complexity. An IS-LDPC code has a number of disjoint invertible subsets, and each invertible subset can be independently inverted to generate other valid codewords of the LDPC code. To construct IS-LDPC codes with good error-correcting performance, we propose a modified progressive edge-growth construction algorithm and verify its effectiveness by analyzing the constructed Tanner graphs. Both theoretical analysis and numerical results show that the IS-LDPC codes exhibit good error-correcting performance and the proposed PAPR reduction scheme based on IS-LDPC codes significantly reduces the PAPR. Compared with the existing coding-based candidate generation schemes, the proposed scheme has a much lower searching complexity when the codeword is transmitted by multiple OFDM symbols. With all mentioned advantages, the proposed PAPR reduction scheme based on IS-LDPC codes could serve as an attractive PAPR reduction solution for future multicarrier communication systems.