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Last name: FERNANDES
First name: Carlos Alexandre Rolim
International audience
Two semi-blind tensor based receivers for uplink radio over fiber (ROF) nonlinear instantaneous channels in a multiuser code division multiple access (CDMA) environment are proposed in this paper. These receivers are based on the PARAFAC decomposition of a tensor (three-way array) composed of received signals with space, time and code...
International audience
Submitted in July 2009
In this paper, a Blind Source Separation (BSS) and channel identification method using second order statistics is proposed for nonlinear multiuser communication channels. It is based on the joint diagonalization of a set of covariance matrices. Modulation codes (constrained codes) are used to ensure the orthogonality of nonlinear combinations...
Multiple-input multiple-output (MIMO) Volterra models have applications in different areas, including telecommunications. An overview of the modeling of nonlinear communication channels using MIMO Volterra models is presented in this paper. First, the development of an equivalent baseband discrete-time representation of a single-input...
One of the main drawbacks of orthogonal frequency division multiplexing (OFDM) systems is the high peak-to-average power ratio (PAPR) of the transmitted signals, which can cause the introduction of inter-carrier interference (ICI) due to the presence of nonlinear power amplifiers (PAs). In this paper, a theoretical analysis of ICI in nonlinear...
International audience
Due to a high peak-to-average power ratio (PAPR), orthog- onal frequency division multiplexing (OFDM) signals are often driven at the nonlinear region of power amplifiers (PAs). As a consequence, the orthogonality between the subcarriers is broken and nonlinear inter-carrier interference (ICI) is introduced. In this paper, we propose two...
This paper presents two blind identification methods for nonlinear memoryless channels in multiuser communication systems. These methods are based on the parallel factor (PARAFAC) decomposition of a tensor composed of channel output covariances. Such a decomposition is possible owing to a new precoding scheme developed for phase-shift keying...
A new method for estimating nonlinear instantaneous channels in a multiuser Code Division Multiple Access (CDMA) environment is presented in this paper. This kind of nonlinear models has important applications in the field of telecommunications, e.g. to model uplink channels in Radio Over Fiber multiuser communication systems. The proposed...
National audience
In this paper, new decision directed algorithms for blind equalization of communication channels are presented. These algorithms use informations about the last decided symbol to improve the performance of the constant modulus algorithm (CMA). The main proposed technique, the so called decision directed modulus algorithm (DDMA), extends the CMA...
National audience
International audience
A multi-hop multi input multi output (MIMO) relay system with tensor coding at the source and relays is proposed in this paper. The tensor of signals received at destination satisfies a new tensor model, called high-order nested Tucker decomposition (HONTD), which generalizes an existing tensor decomposition. Exploiting this HONTD model allows...
This paper proposes two new methods for identifying multiple-input-multiple-output (MIMO) nonlinear systems. Specifically, we are interested in radio over fiber (ROF) uplink communications channels. The electrical optical (E/O) conversion in such systems introduces relevant nonlinear distortion and, consequently, the overall channel can be...
International audience