PAPR Reduction in OFDM Using PTS Combined with Algebraically Constructed QC-LDPC Codes

抄録

Partial transmit sequence (PTS) is an effective technique to mitigate the peak-to-average power ratio (PAPR) problem in orthogonal frequency-division multiplexing (OFDM) systems. Some past research proposed a Q-section coded PTS scheme with the progressive edge-growth (PEG) search algorithm for construction of the employed quasi-cyclic low-density parity-check (QC-LDPC) codes. In this paper, a new approach of the Q-section PTS scheme for PAPR reduction and error correction is devised based on algebraically constructed QC-LDPC codes with masking. The corresponding Q-section constraint is then turned into one only on the masking matrix which is easy to satisfy, based on which QC-LDPC codes can be flexibly constructed and designed without extra search complexity. Our method allows for a single algebraically constructed base matrix to generate a family of Q-section QC-LDPC codes with different lengths and rates. The performance of the constructed codes can be guaranteed by employing analysis such as density evolution. The corresponding efficient ways of encoding and decoding applicable to general QC-LDPC codes are also proposed. Our scheme need not transmit extra side information and has no extra cost compared with the traditional PTS scheme. The PAPR control patterns are embedded in specific bit positions of the codeword so that the information bits can be recovered without attempting all possible control patterns during decoding. Finally, simulation results show that our design can provide better error performance than previous codes and have similar PAPR reduction performance.