Abstract:
Disclosed is an adaptable/variable type modulation/demodulation apparatus, and more particularly, a physical layer transmission apparatus which includes a classification unit to classify a bit stream according to a standard that is determined in advance after receiving the bit stream; an uncoded bit group unit to group the bit stream which is not to be LDPC-coded by a predetermined number of bits; an LDPC encoder to perform LDPC-coding of the bit stream; a coded bit group unit to group the coded bit stream by the predetermined number of bits; a quadrature amplitude modulation (QAM) unit to select a symbol coset using the coded bit groups; and a convolutional interleaver to perform convolutional interleaving of the symbol.