University of California

Stmicroelectronics S.r.l.

Luca Reggiani

Giorgio Betti

Angelo Dati

Augusto Andrea Rossi

Davide Giovenzana

Filippo Brenna

Gian Mario Maggio

A system for decoding digital signals subjected to block coding includes a post-processor that corrects the codewords affected by error, identifying them with the most likely sequence that is a channel sequence and that satisfies a syndrome check. The post-processor is a finite-state machine described by a graph that represents the set of error events. The post-processor evolves in steps through subsequent transition matrices, deleting at each step the paths that accumulate an invalid number of error events or an excessive number of wrong bits, paths that accumulate a total reliability higher than a given threshold, paths with an invalid check on the received sequence, and paths that reveal an invalid syndrome after having reached a maximum number of events.

Process for decoding signals and system and computer program product therefore

A pseudo-chaotic coding/modulation method. The coding method exploits symbolic dynamics of a chaotic map at the transmitter to encode data. The encoding synthesizes the chaotic map based upon the data to be transmitted. In a preferred embodiment, pseudo-chaotic iterates are generated from a digital implementation of a Bernoulli shift map. The output of the shift map is translated by a mapping, preferably implemented by a digital signal processor, to allow transitions between states in a transmitted signal to differ, and the translated map is used to drive a modulator (for example PPM, FSK, PSK, QAM, etc.). In the specific case of pulse-position modulation (PPM) the translated map is used to modulate pulse train positions within a periodic synchronization frame. The preferred embodiment uses a shift register to implement an approximation of the Bernoulli shift map acting as a form of convolutional code with a number of states equal to the symbolic states defined on the chaotic map. A receiver may use fewer states and still decode the data signal, allowing receiver scalability.

Pseudo-chaotic communication method exploiting symbolic dynamics

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Ferrara, Italy

Luca Reggiani