【摘要】 低密度校验码(LDPC)具有编码增益高、译码速度快、性能接近Shannon限的优点。LDPC码应用于OFDM,能有效地提高多径环境下OFDM的BER性能。本文首先简单介绍LDPC码及其概率域上的译码算法,在此基础上对译码算法作融合,阐述概率似然比的译码算法。为了把LDPC应用于OFDM系统上,提出了多电平调制下的LDPC译码的算法。仿真结果表明,在AWGN和Rayleigh信道下,此算法正确有效。更多还原

【Abstract】 The performance of LDPC (Low Density Parity Check) coding is very close to the Shannon limit with low practical decoding complexity. When LDPC codes are applied to OFDM, the bit error rate (BER) of OFDM in multi-path environments can be improved effectively. An iterative decoding algorithm for the LDPC-OFDM systems with MQAM/MPSK is proposed in this paper. It is shown from simulation that the proposed algorithm for LDPC-OFDM systems with multilevel modulation works correctly both in AWGN and Rayleigh fading channels.更多还原