U.S. Philips Corporation

David Gianella

Antoine Chouly

Americo Brajal

Trellis coded QAM using rate compatible, punctured, convolutional codes

A digital transmission system wherein the transmitter applies a systematic convolutional code to the input data to generate a product code in blocks, with trellis closure by adding redundant data comprising a parity code bit. The thus coded data are then allocated to symbols that have undergone multidimensional digital modulation. At the receiver, iterative decoding is performed in cascade along two paths by computing hard decision reliabilities for each sub-set of the multidimensional digital modulation so as to produce soft decisions. The second path utilizes the results produced by the first path to form soft decisions. The soft decisions enable determination of output symbols. The invention also relates to a data protection method implemented in such a system.

Digital transmission system and method comprising a product code

A digital transmission system which provides transmission error protection for transmitted data. The input data is encoded using a punctured systematic convolutional trellis code. Row and column components of a matrix formed by the encoded input data are then used to generate a product code in blocks, with trellis closure by addition of redundant data. The data thus encoded is then allocated to quadrature amplitude modulation symbols. At the receiver end the transmitted modulation symbols are decoded by iterative decoding, the reliability of hard decisions being computed so as to provide generation of soft decision output symbols.

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Dannemarie, France

David Gianella