Performance Improvement of Multi-level Redundant Discrete Wavelet Transform OFDM System by Using LDPC Encoding and Belief Propagation Algorithm

Orthogonal frequency division multiplexing (OFDM) is extensively researched by scholars because of its strong anti-fading ability, anti-interference ability and high frequency band utilization. Based on the discrete wavelet transform orthogonal frequency division multiplexing (DWT-OFDM) all these years, a variety of improved systems have emerged one after another. But the disadvantage is that coding technology has not been effectively applied in these systems. In this paper, We choose multilevel redundant discrete wavelet transform orthogonal frequency division multiplexing (ML-RDWT-OFDM) system as the research object, low-density Parity-check (LDPC) coding and soft decision (SD) decoding of belief propagation algorithm are introduced to increase the ML-RDWT-OFDM performance factor. The uncoded and coded ML-RDWT-OFDM systems are simulated to verify that the coding scheme does improve the performance.