Alternating multiuser detection with iterative soft interference cancellation for highly loaded dual-signaling MIMO CDMA systems

This paper presents an effective multiuser detector (MUD) for the uplink of dual-signaling multiple-input multiple-output (MIMO) code division multiple access (CDMA) systems over multipath fading channels, where the data are transmitted using either the spatially multiplexing (SM) or the space-time block code (STBC) scheme. The new MUD first separates users into two groups according to their transmission signaling schemes and then alternatively detects the users in each group with the removal of iteratively refined soft information-assisted multiple access interferences (MAI) to enhance the interference cancellation capability. Moreover, for practical low-complexity implementations, the users in each group are further partitioned into smaller subgroups to reduce the the computational load. Conducted simulations show that the proposed MUD can render superior performance compared with previous approaches, especially in highly loaded scenarios.