Date Added: Oct 2012
OFDM with Quadrature Amplitude Modulation (QAM) technique can be used for high speed optical applications. Increasing the order of modulation, the Bit Error Rate (BER) increases. Forward Error Correction (FEC) coding like LDPC coding is generally used to improve the BER performance. LDPC provides large minimum distance and also the power efficiency of the LDPC code increases significantly with the code length. In this paper, the authors have compared the soft decision and hard decision algorithms of LDPC codes.