Sequential decoding with stack reordering

A method of sequentially decoding a data signal received through a transmission channel in a communication system, said received data signal carrying transmitted symbols, said method comprising determining 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 the 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 received data signal and each node being associated with a predetermined respective 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,

• and wherein said method further comprising monitoring at least one stack reordering activation condition and, in response to a stack reordering activation condition being verified:
• reducing the metric associated with each node stored in the stack by a quantity,
• reordering the stack by increasing value of the reduced metric, and
• removing a set of nodes from the reordered stack so as to maintain a number of nodes in the reordered stack, the maintained nodes corresponding to the nodes having the lowest metrics in the reordered stack.

A computer program product for sequentially decoding a data signal received through a transmission channel in a communication system, said received data signal carrying transmitted symbols, said estimated symbols being determined from nodes of a decoding tree based on a weight metric associated with each of said node, the computer program product comprising:

• a non-transitory computer readable storage medium;
• and
• instructions stored on the non-transitory computer readable storage medium that, when executed by a processor, cause the processor 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 the 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 received data signal and each node being associated with a predetermined respective 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,
• wherein said processor is further caused to monitor at least one stack reordering activation condition and, in response to a stack reordering activation condition being verified:
• to reduce the metric associated with each node stored in the stack by a quantity,
• to reorder the stack by increasing value of the reduced metric, and
• to remove a set of nodes from the reordered stack so as to maintain a number of nodes in the reordered stack, the maintained nodes corresponding to the nodes having the lowest metrics in the reordered stack.