J. A. Rodriguez - Fonollosa

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In this paper, we investigate the average bit error rate (BER) performance of spatial multiplexing MIMO systems with CSI at both sides of the link. Such systems result from the use of a multiple beamforming strategy that exploits the channel eigenmodes or, in other words, from the use of joint transmit-receive linear signal processing techniques in(More)
Following the pioneering work of Zheng and Tse, this paper derives the diversity and spatial multiplexing gain tradeoff for MIMO systems employing a multiple beamforming scheme. This result is obtained looking at the channel performance limits when both the SNR and the transmission rate tend to infinity, such that the relation between the rate and the(More)
The computation of the channel capacity of discrete memoryless channels is a convex problem that can be efficiently solved using the Arimoto-Blahut (AB) iterative algorithm. However, the extension of this algorithm to the computation of capacity regions of multiterminal networks is not straightforward since its computation gives rise to non-convex problems.(More)
The provision of high capacity, low cost and reliable wireless multimedia communication for bursty packet traffic (as well as voice and delay constrained streaming traffic) continues to be a challenging aspect of future wireless communications systems. In this sense, structured and ad-hoc multihop networks and intelligent relaying are expected to play a(More)
Aim of this contribution is to illustrate the state of the art of smart antenna research from several perspectives. The bow is drawn from transmitter issues via channel measurements and modeling, receiver signal processing, network aspects, technological challenges towards first smart antenna applications and current status of standardization. Moreover,(More)
This work derives a tight upper bound on the diversity and spatial multiplexing gain for MIMO systems when the transmitter has perfect channel knowledge, generalizing the pioneering work of Zheng and Tse developed in the context of no channel state information at the transmit side. This result is obtained looking at the channel performance limits when both(More)
A technique for downlink transmission beamformer design in cellular mobile communications systems using an antenna array at the base station is presented. The method is based on estimation of an underlying spatial distribution associated with each source's spatial downlink channel. The algorithm is "blind" in the sense that it depends only on uplink spatial(More)
The allocation of network resources for spectral efficiency maximization in a broadcast channel under the practical restrictions of orthogonal transmission and the use of squared QAM constellations is addressed. Given a total transmit power constraint and (possibly) different per-user quality of service requirements in the form of target uncoded bit error(More)
In this paper, a blind algorithm for detecting active users in a DS-CDMA system is presented. This probabilistic algorithm relies on the theory of hidden Markov models (HMM) and is completely blind in the sense that no knowledge of the signature sequences, channel state information or training sequences is required for any user. Additionally, observation(More)