Linear group-wise successive interference cancellation in CDMA

Regularization property of linear interference cancellation detectors

“…Therefore, the performance of the LPIC detector is expected to improve at early stages but after a certain number of stages the noise starts dominating the solution and deteriorating the performance of the LPIC detector. This explains the phenomenon pointed out in [11][12][13][14][15][16], which we call here the semi-convergence property of the LPIC detector.…”

“…An important phenomenon that was noticed in the literature of linear IC detectors is their semi-convergence behavior, i.e., the best Bit Error Rate (BER) is obtained prior to convergence. This phenomenon was noticed first in [11][12][13][14][15], and recently in [16], and it seems to be a common feature in most linear IC's if some conditions are met. However, no study has been yet carried out to explain the roots of this phenomenon and to devise necessary conditions for its occurrence.…”

Analysis of the Linear GSIC Multiuser Detector Using a Matrix Iterative Approach

“…Up to our knowledge, no theorem for the convergence of such scheme exists in the literature and thus we propose two new corollaries that extend the famous work of Kahan [14] to the case where the relaxation factor is a matrix instead of a scalar. By using the new corollaries we derive two new conditions of convergence for the linear GSIC and we show as well that the conditions of convergence obtained in [10] and [13] can also be obtained by using our approach. This will be in fact a unified approach for the analysis of any GSIC detector.…”

“…In this work we show, by using a matrix iterative analysis approach, that the linear GSIC scheme proposed in [10] is in fact equivalent to a modified block successive over-relaxation iterative method where the relaxation factor is a matrix instead of a scalar. Up to our knowledge, no theorem for the convergence of such scheme exists in the literature and thus we propose two new corollaries that extend the famous work of Kahan [14] to the case where the relaxation factor is a matrix instead of a scalar.…”

“…The authors in [10] suggested a chip-level linear GSIC detection scheme and showed that if the proposed structure converges it converges to the decorrelator detector. Four group detection schemes were identified in [10], namely: the linear group-decorrelator successive interference cancellation (GDEC-SIC) detector, the linear group minimum mean square error successive interference cancellation (GMMSE-SIC) detector, the linear group parallel interference cancellation successive interference cancellation (GPIC-SIC) detector and finally the linear group matched filter successive interference cancellation (GMF-SIC) detector. It has been shown that only the linear GDEC-SIC detector is always stable, for the other group detectors there is no guarantee of convergence.…”