Invertible Subset QC-LDPC Codes for PAPR Reduction of OFDM Signals

Abstract

A type of invertible subset low density parity-check (IS-LDPC) codes was proposed to reduce the peak-to-average power ratio for orthogonal frequency-division multiplexing systems with low complexity recently, where the key idea is that each invertible subset can be independently inverted to generate other valid codewords of the LDPC code. In this paper, we firstly extend the idea of invertible subsets to quasi-cyclic LDPC (QC-LDPC) codes, and this new family of QC-LDPC codes is called as invertible subset QC-LDPC (IS-QC-LDPC) codes. Moreover, we propose two types of subset partitioning and deeply discuss the properties of IS-QC-LDPC codes with different subset partitioning. After declaring that interleaved partitioning is more appropriate for IS-QC-LDPC codes than the block partitioning, we propose a novel progressive edge graph-like algorithm to construct good IS-QC-LDPC codes with interleaved partitioning. The simulation results show that the IS-QC-LDPC codes exhibit good error-correcting performance, which is very close to that of the corresponding QC-LDPC codes of the IEEE 802.16e, for a wide range of subset number.