This thesis proposes two algorithms for recovering an acoustic signal from multiple blind measurements made by sensors (microphones) over an acoustic channel. Unlike other algorithms that use a posteriori probabilistic models to fuse the data in this problem, the proposed algorithms use results obtained in the context of data communication theory. This constitutes a new approach to this sensor ...

In performing blind equalization, we propose a direct channel estimation method based on entropy-maximization of input signal with its known probability density function. That is, the proposed method estimates filter coefficients of the channel instead of equalizing filter coefficients which most of equalization methods try to estimate. Because the channel usually has a much shorter length than...

In many applications, observed signals are contaminated by both random noise and blur. This paper proposes a blind deconvolution procedure for estimating a regression function with possible jumps preserved, by removing both noise and blur when recovering the signals. Our procedure is based on three local linear kernel estimates of the regression function, constructed from observations in a left...

Steganography is used to hide the occurrence of communication. Discovering and rendering useless such covert message is an art of steganalysis. The importance of techniques that can reliably detect the presence of secret messages in images is increasing as images can hide a large amount of malicious code that could be activated by a small Trojan horse type of virus and also for tracking crimina...

This contribution elaborates on the concept of blind identi"cation of multiple FIR channels with transmission "lter knowledge (WTXFK). This prior knowledge could, in fact, include not only the transmitter (TX) (pulse shaping) "lter but also the receiver (RX) "lter present in digital communication systems. Exploitation of this side information allows the estimation to concentrate on the impulse ...

An algorithm for estimating the basis vectors used in the Karhunen-Loeve Transform (KLT) is described. The algorithm is “blind” in the sense that it utilizes minimal information about the data vector being encoded. It is capable of estimating the KLT basis vectors using only the KLT coefficients and one additional scalar quantity. This eliminates the need to repeatedly encode and transmit the K...

The problem of channel estimation in code-division multiple-access (CDMA) systems is considered. Using only the spreading code of the user of interest, a technique is proposed to identify the impulse response of the multipath channel from the received data sequence. While existing blind methods suffer from high computational complexity and sensitivity to accurate knowledge of the noise subspace...

Multiantenna wireless systems have shown great promise in achieving high rates. We consider an OFDM multiple transmit/receive antenna system. We propose a linear non-redundant block precoding scheme, that is applied at the input of the OFDM system. The coding spreads the symbols of each user over all subcarriers, thus increasing multipath diversity, and at the same time introduces some structur...

For the case of white uncorrelated inputs, most of the blind multichannel identification techniques are not very robust and only allow to estimate the channel up to a number of ambiguities, especially in the MIMO case. On the other hand, all current standardized communication systems employ some form of known inputs to allow channel estimation. The channel estimation performance in those cases ...