Robust blind multiuser detection for synchronous CDMA systems

The performance of blind multiuser detection methods is known to degrade in the presence of mismatches between the actual and the presumed desired user signatures. Such mismatches may occur in practical situations due to an imperfect knowledge of the channel impulse response. We propose a new robust approach to blind multiuser detection in the presence of unknown arbitrary-type mismatches of the desired user signature. The formulations of our robust multiuser receivers are based on the explicit modeling of uncertainties in the covariance matrix of the desired user signature/data covariance matrix and optimization of the worst-case performance. The proposed methods have a computational complexity comparable to that of the traditional blind multiuser detection algorithms, while offering an improved robustness and faster convergence rates.