Elisabeth de Carvalho

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—This paper studies linear transmit filter design for Weighted Sum-Rate (WSR) maximization in the Multiple Input Multiple Output Broadcast Channel (MIMO-BC). The problem of finding the optimal transmit filter is non-convex and intractable to solve using low complexity methods. Motivated by recent results highlighting the relationship between mutual(More)
—We introduce a new two–step relaying scheme based on superposition coding, SC–relaying. In Step 1, the source AS broadcasts a message, created by superposition coding, to the relay AR and the destination AD. After decoding the information from AS, AR relays a part of this message in Step 2, by using a codebook that is adapted to the link AR − AD. The(More)
— This paper investigates the problem of blindly and semi–blindly acquiring the channel gains for an underdetermined synchronous multiuser multicarrier system. The special case of a MISO (Multiple Input Single Output) channel is considered where the different users transmit at the same time and in the same bandwidth. In order to separate the different users(More)
—This paper studies various cooperative diversity schemes for Orthogonal Frequency Division Multiple Access (OFDMA)-Time Division Duplex (TDD) based two-hop cellular networks in low mobility scenarios, where the instantaneous channel state information is available at the base station. A user scheduling and radio resource allocation technique is developed in(More)
We pursue our Iterative Quadratic Maximum Likelihood IQML approach to blind estimation of multiple FIR channels. We use a parameterization of the noise subspace in terms of linear prediction quantities. This parameteriza-tion is robust w.r.t. a channel length mismatch. Specifically , when the channel length is overestimated, no problems occur.(More)
— Two channel estimation methods are often opposed: training sequence methods which use the information induced by known symbols and blind methods which use the information contained in the received signal, and possibly hypotheses on the input symbol statistics, but without integrating the information from known symbols, if present. Semi–blind methods(More)
We investigate Maximum Likelihood (ML) methods for blind and semi-blind estimation of multiple FIR channels. Two blind De-terministic ML (DML) strategies are presented. In the first one, we propose to modify the Iterative Quadratic ML (IQML) algorithm in order to " denoise " it and hence obtain consistent channel estimates. The second strategy, called(More)