Institut Mines-telecom

Asma Mejri

Ghaya Rekaya Ben-Othman

Mohamed-Achraf Khsiba

Ghaya Rekaya-Ben Othman

Mohammed-Achraf Khsiba

There is provided a method of generating a space-time block code (STBC) for encoding a digital data sequence comprising a set of independent symbols to be transmitted through a transmission channel in a communication system, the space-time block code being represented by a set of linear dispersion matrices in a linear dispersion representation, each linear dispersion matrix comprising components having complex values, the method comprising, generating at least some of the linear dispersion matrices depending on component-wise conditions related to a set of selected pairs of the linear dispersion matrices, each pair comprising a first linear dispersion matrix and a second linear dispersion matrix, said component-wise conditions comprising a component-wise condition between the components of the first linear dispersion matrix and the components of the second linear dispersion matrix.

Space-time coding for communication systems

There is provided a decoder for decoding a data signal received through a transmission channel in a communication system, the decoder () comprising a symbol estimation unit () configured to determine estimated symbols representative of the transmitted symbols carried by the received signal, the estimated symbols being determined from nodes of a decoding tree based on a weight metric associated with each of the node. The decoder further comprises a termination alarm monitoring unit () for monitoring a termination alarm depending on the current decoding computation complexity, the termination alarm being associated with a metric parameter, the symbol estimation unit being configured to reduce the weight metric of each node of the decoding tree by a quantity corresponding to a function of the metric parameter associated with the termination alarm, in response to the triggering of the termination alarm.

Anticipated termination for sequential decoders

A method, device, and a computer program are provided to decode a signal received through a transmission channel in a communication system, the received signal being represented by a signal vector. The method comprises:

Tree search-based decoding

Embodiments of the invention provide a decoder for decoding a signal received through a transmission channel in a communication system, said signal comprising a vector of information symbols, said transmission channel being represented by an upper triangular matrix, wherein the decoder comprises:

Methods and devices for sub-block decoding data signals

There is provided a decoder () for sequentially decoding a data signal received through a transmission channel in a communication system, the received data signal carrying transmitted symbols, the decoder comprising a symbol estimation unit () configured to determine estimated symbols representative of the transmitted symbols carried by the received signal from information stored in a stack, the stack being filled by iteratively expanding child nodes of a selected node of a decoding tree comprising a plurality of nodes, each node of the decoding tree corresponding to a candidate component of a symbol of the received data signal and each node being associated with a predetermined metric, the stack being filled at each iteration with at least some of the expanded child nodes and being ordered by increasing values of the metrics associated with the nodes, the selected node for each iteration corresponding to the node having the lowest metric in the stack. The decoder further comprises a stack reordering activation monitoring unit () configured to monitor at least one stack reordering activation condition and, in response to a stack reordering activation condition being verified, to cause the symbol estimation unit to:

Sequential decoding with stack reordering

A decoder or a decoding method for decoding a data signal is provided by iteratively constructing a decoding tree comprising nodes, each representing a component of a symbol of a data signal, each iteration comprising, for a current node of the tree stored in the top of the stack; generating a reference child node of the current node from the data signal; from the reference child node, generating a first and second neighbor child nodes by subtracting/adding a positive integer parameter from/to the value of the reference node; storing in the stack three child nodes derived from the reference, first and second neighbor child nodes, the nodes stored in the stack being ordered by increasing values of a node metric; removing the current node stack; selecting the top node of the stack as the new current node. The data signal is estimated from the stack node information.

Methods and systems for decoding a data signal based on the generation of a decoding tree

The invention relates to a MAP decoding method of a signal received through a noisy channel, the signal being composed of symbols in an alphabet having a non-uniform probability distribution, the symbols being represented by points in a lattice (&#x39b;). The probability distribution of symbols is modeled using a Gaussian distribution. An augmented lattice (&#x39b;) is formed from the lattice (&#x39b;) and the ratio (&#x3b2;) between variance of the noise and variance of the Gaussian distribution of symbols. Therefore, the disclosed MAP decoding method consists essentially of decoding using an ML criterion searching the point in the augmented lattice closest to the point representative of the received signal (y).

Map decoding method using augmented lattices

An exemplary decoder is provided for decoding a signal received through a transmission channel in a communication system. The exemplary decoder comprises a transformation unit configured to determine a set of auxiliary channel matrices, each auxiliary channel matrix being determined by performing a linear combination of at least one of the column vectors of the channel matrix; a decomposition unit configured to determine a decomposition of each auxiliary channel matrix into an upper triangular matrix and an orthogonal matrix; a matrix selection unit configured to select at least one auxiliary channel matrix among the set of auxiliary channel matrices depending on a selection criterion related to the components of the upper triangular matrices. The decoder determines at least one estimate of vector of information symbols from an auxiliary signal and from the upper triangular matrix corresponding to a selected auxiliary channel matrix by applying a decoding algorithm.

Methods and devices for decoding data signals

Embodiments of the invention provide a decoder () for decoding a signal received through a transmission channel in a communication system, the signal carrying information symbols selected from a given set of values and being associated with a signal vector, the transmission channel being represented by a channel matrix. The decoder comprises: The at least one symbol estimation unit is configured to apply at least one iteration of a sequential decoding algorithm, the sequential decoding algorithm comprising iteratively filling a stack by expanding child nodes of a selected node of a decoding tree comprising a plurality of nodes, each node of the decoding tree corresponding to a candidate component of a symbol of at least a part of the received signal and each node being assigned an initial metric. The symbol estimation unit is further configured to calculate a modified metric for at least one node of the expanded child nodes from the metric associated with the at least one node and from the sub-block weighting coefficient calculated for the sub-vector to which the at least one node belongs, symbol estimation unit being configured to assign the modified metric to the at least one node.

Weighted sequential decoding

Embodiments of the invention provide a decoder for decoding a signal received through a transmission channel in a communication system, said signal comprising a vector of information symbols, wherein the decoder comprises:

There is provided a decoder for sequentially decoding a data signal received through a transmission channel in a communication system, said data signal carrying transmitted symbols, said decoder comprising a symbol estimation unit () configured to determine estimated symbols representative of the transmitted symbols carried by the received signal from information stored in a stack, said symbol estimation unit () being configured to iteratively fill the stack by expanding child nodes of a selected node of a decoding tree comprising a plurality of nodes, each node of the decoding tree corresponding to a candidate component of a symbol of said data signal and each node being assigned a metric, the stack being filled at each iteration with a set of expanded child nodes and being ordered by increasing values of the metrics assigned to the nodes, the selected node for each iteration corresponding to the node being assigned the lowest metric in the stack, the decoder comprising a metric determination unit () configured to determine an initial metric for each child node of said set of expanded child nodes, wherein the decoder further comprises a modified metric calculation unit () configured to calculate a modified metric for at least one of the expanded child nodes from the metric associated with said expanded child node and a weighting coefficient, said weighting coefficient being a function of the level of said node in the decoding tree, the decoder assigning said modified metric to said at least one of the expanded child nodes.

Parameterized sequential decoding

Embodiments of the invention provides a decoder for decoding a signal received through a transmission channel in a communication system, said signal carrying information symbols selected from a given alphabet and being associated with a signal vector, said transmission channel being represented by a channel matrix, wherein said decoder comprises:

Semi-exhaustive recursive block decoding method and device

Embodiments of the invention provide a decoder for decoding a data signal received through a transmission channel in a communication system, said transmission channel being represented by an upper triangular matrix, said signal carrying transmitted symbols, each symbol carrying a set of information bits, wherein said decoder comprises:

Recursive sub-block decoding

Embodiments of the invention provide a decoder for decoding a signal represented by a vector of information symbols received through a transmission channel in a communication system, said the transmission system being represented by a channel state matrix, said information symbols being selected from a given set of values carrying a set of information bits, wherein said decoder comprises: The decoder being configured to determine at least one estimate of a vector of transmitted information symbols from said at least one estimate of each sub-vector of information symbols.

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Antibes, France

Asma Mejri