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This paper investigates adaptive Beamforming techniques used in concatenation with a ppSNR-based switching algorithm in multi-user MIMO OFDM systems. The performance's equivalence of SM adaptive beamforming and STBC adaptive one is shown analytically and by simulation, and a complexity study is carried out and allows selecting the beamforming adapted to SM. The effect of the MIMO architecture (with...
In this paper, we propose two methods to perform a switching between spatial multiplexing and MIMO diversity in order to improve performances of a 2×2 OFDM-MIMO system. Each method is defined depending on the granularity of the spatial processing. The comparison of BER performances of the two schemes leads to the choice of the sub-carrier based switching processing which gives the most significant...
Performances and capacity of MIMO-OFDM systems are enhanced with adaptive MIMO techniques such as Demmel condition number based switching algorithm. In this paper we show that the complexity of this algorithm can be reduced by using the 2-norm condition number of the channel matrix as the selection metric. Simulation results show that using this selection criterion, the switching algorithm offers...
This paper proposes an advanced OFDM-MIMO reconfigurable architecture that uses an adaptive switching algorithm between diversity and spatial multiplexing. The transmitter blocs' specifications such as the MIMO technique and the modulation scheme are adjusted according to the channel state, which gives a practical cognitive radio strategy. The system cost- efficiency is performed by the application...
This paper presents a study of switching algorithm performances when combined to several beamforming techniques in a multi-user MIMO communication system. The study of three beamforming solutions shows that the beamforming processing has an important influence in the decision criterion of the switching algorithm. The STBC adaptive beamforming, which is better than Zero forcing (ZF) and Singular Value...
This paper presents an extra processing added to conventional LS estimation to improve its performances in OFDM-MIMO systems. The new technique is based on the knowledge of the power delay profile. The application of the improved estimator is useful when employing advanced MIMO adaptation techniques such switching algorithms and leads to significant improvement in decision criterion precision and...
The data that is transmitted in PLC systems is subject to corruption by impulsive noise. Many techniques were proposed to correct its effect. In this paper, we propose the use of a modified erasure algorithm to shield PLC system from noise bursts. Apart its performance to correct burst errors, this algorithm presents the advantage of reducing the end- to-end delay of the system.
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