Roland Gautier

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Turbo-codes are error-correcting codes used in powerful digital transmission systems to ensure a low binary error rate. This paper presents different approaches aimed at recovering a convolutional encoder in a non-cooperative context; it also explains the residual inde-termination due to " equivalent " coders. Moreover, it reports on a new approach(More)
— This paper deals with the problem of blind multiuser detection in multirate direct-sequence code division multiple access (DS-CDMA). Direct-Sequence Spread Spectrum (DS-SS) signals are well-known for their low probability of interception: their statistics are similar to those of a noise; furthermore, they are usually transmitted below the noise level.(More)
In order to enhance the reliability of digital transmissions, error correcting codes are used in every digital communication system. To meet the new constraints of data rate or reliability, new coding schemes are currently being developed. Therefore, digital communication systems are in perpetual evolution and it is becoming very difficult to remain(More)
—To enhance the quality of transmissions, all digital communication systems use error-correcting codes. By introducing some redundancy in the informative binary data stream, they allow one to better withstand channel impairments. The design of new coding schemes leads to a perpetual evolution of the digital communication systems and, thus, cognitive radio(More)
A self recovering receiver for encoded and scrambled binary data streams is proposed in this paper. The generating polynomial of the scrambling sequence is known, as well as the encoder structure and coefcients, but the scrambler time offset is unknown. Taking prot of redundancy introduced by the encoder, we propose a method which is able to estimate the(More)
—For enhancement of the quality of digital transmissions , standards are in continual evolution, which generates compatibility problems. Cognitive radio systems permit one to solve this problem through the design of intelligent receivers. However, such receivers must be able to adapt themselves to a specific transmission context. This requires the(More)