Low Density Parity Check Decoding Algorithm for Multi-level Modulation Scheme

LDPC decoding for 8PSK, received symbols are split bit by bit based using the received in-phase and quadrature components. The method of bit-splitting is affects on decoding performance because its method depend on distance over symbol constellation. This paper proposes the bit split method using the sector information with sacrifice a little performance loss compared to Euclidean distance method. Furthermore DVB-S2 Digital Video Broadcasting specification supports BC(Backward Compatible) mode which using the hierarchical modulation method, this paper also analyzes the decoding performance according to deviation angle of 8PSK constellation for various LDPC coding rates.