Catalin Lacatus

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In this paper, we present an adaptive algorithm for interference avoidance, which can be applied in a distributed manner by active users in a CDMA wireless system to obtain optimal codewords and powers for specified target signal-to-interference plus noise ratio (SINR). The algorithm is derived using a game-theoretic approach in which separable cost(More)
The paper presents a distributed algorithm for joint codeword and power adaptation in the uplink of a code division multiple access (CDMA) system, in which users sequentially adjust codewords and powers using gradient-based updates to maximize their individual spectral efficiency subject to constraints on the signal-to-interference plus-noise ratios (SINR).(More)
A definition of total weighted square correlation (TWSC) for an overloaded multicellular synchronous DS-CDMA system in the presence of multipath on the uplink is introduced. We assume the channel state information is known perfectly both at transmitter and receiver. The optimum solutions for minimizing TWSC are the orthogonal generalized WBE (Welch bound(More)
— The paper presents an interference avoidance algorithm for codeword and power adaptation in the uplink of a Code Division Multiple Access (CDMA) system with variable number of active users. The algorithm tracks changes in the system configuration, and transitions incrementally from one optimal point corresponding to a given number of active users to a new(More)
The paper presents a distributed algorithm that allocates the minimum user powers for the optimal codewords in the uplink of a code division multiple access (CDMA) system. The user cost function will be the user power written as a convex function of user codeword for a defined signal-to-interference plus-noise ratios (SINR) target. The optimization problem(More)
The aim of this study was to evaluate the in vitro activity of cefotaxime, ceftriaxone, ceftazidime, ceftibuten and aztreonam against the clinical isolates of Enterobacteriaceae. MICROORGANISMS: A total of 973 enterobacteria isolated from clinical material (urine and faeces) were tested. Strains were collected during 1996-1998 period, in some centers of(More)