Multiuser detection techniques with decision statistics combining for layered space‐time coded CDMA systems

Abstract

AbstractThis paper considers a low‐complexity iterative multiuser detection/decoding algorithm in single user layered space‐time coded (LST) systems and LST coded code division multiple access (CDMA) systems. We concentrate on the iterative multiuser receiver based on parallel interference cancellation (PIC) and compare it to the iterative PIC with the minimum means square error (MMSE) detection, as these two approaches seem to be most efficient in meeting the performance‐complexity trade‐off required by practical systems. In iterative PIC structures, a decision statistics bias severely limits the system performance for a large number of multiple access (MA) or multiple‐input multiple‐output (MIMO) interferers. A decision statistics combining (DSC) method, originally proposed for iterative PIC receivers in CDMA systems, is used to minimize the bias effect in space‐time coded systems for iterative PIC receivers. Significant performance improvements have been confirmed with the iterative PIC receiver with DSC (PIC‐DSC) relative to the standard iterative PIC receivers in LST systems for both flat and frequency selective fading channels. This advantage is retained in layered coded CDMA systems as well. The proposed iterative PIC‐DSC detector approaches the performance of the much more complex iterative PIC‐MMSE receiver. Copyright © 2006 AEIT.