Joel Lienard

An informed synchronization scheme for audio data hiding

This paper deals with the problem of synchronization in the particular case of audio data hiding. In this kind of application the goal is to increase the information of an audio data set by inserting an imperceptible message. An innovating synchronization scheme that uses informed coding theory is proposed. The goal is to realize a complementary approach from two different techniques in order to obtain an enhanced synchronization system. To that end, the analysis of the classical spread spectrum synchronization is done and this classical scheme is improved by the use of side information. Informed coding theory is presented and revisited taking into account the problem of synchronization to enable the selection of signal realizations called Feature Time Points (FTP) which are correlated with a code. Such considerations yield to the definition of informed synchronization. The proposed scheme and the definition of FTP are after presented taking into account the robustness criterion. Finally, results and comparison with classical spread spectrum synchronization schemes are presented.

Performance evaluation of different channel coding schemes for time-varying multipath channels in UMTS/TDD

We study the behaviour of a UMTS/TDD synchronous downlink receiver, under different scenarios. Computer simulations were conducted to compare the overall system performances obtained with turbo coding to the convolutional coded and channel non coded systems. The propagation environment is a six-path channel with Rayleigh fading amplitudes and fixed delays. Moreover, we propose a method for reducing the iteration number via a cyclic redundancy check (CRC), and estimate the channel decoding complexity to be expected, for different channel conditions.