Patent ID: 6269129
Filing Date: 2001-07-31
Classification: H03M,H04L

Abstract:
A quadrature amplitude modulation (QAM) trellis coded modulation (TCM) decoder for decoding a stream of QAM TCM signals, each of the signals having a plurality of associated branch metrics, each signal having an in-phase component and a quadrature component, wherein the in-phase component is defined by a plurality of in-phase symbols and the quadrature component is defined by a plurality of quadrature symbols, the decoder comprising:a first Viterbi decoder configured to receive an in-phase component of a QAM TCM signal for decoding the associated in-phase symbols into an in-phase decoded bit and a plurality of uncoded in-phase bits;a second Viterbi decoder configured to receive a quadrature component of the QAM TCM signal for decoding the associated quadrature symbols into a quadrature decoded bit and a plurality of uncoded quadrature bits;a QAM demodulator adapted to receive the stream of QAM TCM signals for sequentially converting each of the QAM TCM signals into an associated in-phase component and an associated quadrature component, wherein the associated in-phase component is defined by a plurality of in-phase symbols and the quadrature component is defined by a plurality of quadrature symbols;a first depuncture circuitry coupled to the QAM demodulator to receive the in-phase component for adaptively depuncturing the associated in-phase symbols as inputs for the first Viterbi decoder;a second depuncture circuitry coupled to the QAM demodulator to receive the quadrature component for adaptively depuncturing the associated quadrature symbols as inputs for the second Viterbi decoder;a first serial-to-parallel circuitry coupled to the first depuncture circuitry to receive the in-phase symbols for arranging the in-phase symbols from a serial sequence into a parallel sequence for input into the first Viterbi decoder; anda second serial-to-parallel circuitry coupled to the second depuncture circuitry to receive the quadrature symbols for arranging the quadrature symbols from a serial sequence into a parallel sequence for input into the second Viterbi decoder.