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.
Abstract:
Provided is a method for searching for an optimal coder suitable to a dual stream transmission method of a DTV transceiving apparatus, and an encoder and a decoder employing the optimal coder searching method. The optimal coder searching method includes the steps of: a) determining a mixed pattern of normal stream and robust stream; b) determining a trellis structure of the robust stream which is applied to the mixed pattern based on how coders are connected; c) forming a dual stream trellis by mixing a trellis of the normal stream, which is a normal stream trellis, and a trellis of the robust stream, which is a robust stream trellis; d) computing a free distance at departing points of the dual stream trellis structure based on a dual stream free distance computation termination condition; and e) determining the optimal coder based on the free distance.
Abstract:
Provided are a method of estimating an encoder for dual stream transmission, and an encoder using the same. The method includes the steps of : a) setting up the number of memories required for an encoder, a free distance condition for robust data, and a free distance condition for mixed stream of robust data and normal data; b) obtaining 1/2 rate encoder combinations that sustain backward compatibility with a typical trellis encoder; c) obtaining encoder combinations H that satisfy the free distance condition for the robust data and the free distance condition for the mixed stream from the 1/2 rate encoder combinations; d) obtaining relations between memories and input/output signals, which satisfy the encoder combinations H; and e) configuring an encoder according to the obtained relation between the memories and the input/output signals.
Abstract:
Provided is a method for searching for an optimal coder suitable to a dual stream transmission method of a DTV transceiving apparatus, and an encoder and a decoder employing the optimal coder searching method. The optimal coder searching method includes the steps of: a) determining a mixed pattern of normal stream and robust stream; b) determining a trellis structure of the robust stream which is applied to the mixed pattern based on how coders are connected; c) forming a dual stream trellis by mixing a trellis of the normal stream, which is a normal stream trellis, and a trellis of the robust stream, which is a robust stream trellis; d) computing a free distance at departing points of the dual stream trellis structure based on a dual stream free distance computation termination condition; and e) determining the optimal coder based on the free distance.