L. Rugini, P. Banelli, S. Cacopardi

Regularized MMSE multiuser detection using covariance matrix tapering

The linear minimum mean-squared error (MMSE) detector for direct-sequence code-division multiple-access (DSCDMA) systems relies on the inverse of the covariance matrix of the received signal. In multiuser environments, when few samples are available for the covariance estimation, the matrix illconditioning may produce large performance degradation. In order to cope with this effect, we propose ...

Improved performance of MMSE multiuser receivers for asynchronous CDMA: preliminary results

The Minimum Mean Square Error (MMSE) multiuser detector has received great attention in the last years as the optimum linear solution for reducing the Multiple Access Interference (MAI) in DS-CDMA systems. In asynchronous frequency selective channels the covariance matrix estimation errors may introduce BER performance degradation. Aim of this paper is to outline such degradation and to improve...

Performance analysis of the decorrelating multiuser detector for nonlinear amplified DS-CDMA signals

This paper analyses the effects of the nonlinear distortions introduced by high-power amplifiers (HPAs) on the performance of the linear decorrelating multiuser detector (MUD) in synchronous direct-sequence code-division multipleaccess (DS-CDMA) systems. By assuming and motivating the Gaussian distribution of the nonlinear distortion noise, the system bit-error rate (BER) has been derived theor...

Comparison of Wlan Multicarrier Ds-ss Physical Layer Configurations in Measured Indoor Environment

OPTIMUM OUTPUT POWER BACK-OFF in NON-LINEAR CHANNELS for OFDM BASED WLAN

Cyclically extended OFDM based WLAN systems have the capability to easily counteract frequency selective fading channels by one-tap equalizers in the frequency domain. Conversely, the sensitivity to nonlinear distortions, mainly introduced by power amplifiers, is one of the drawbacks of this modulation technique. Usually, the optimum Output power Back Off (OBO) is the one that minimizes the Tot...