Iterative detection of generalized coded MIMO signals using a widely linear detector

We investigate an iterative receiver with a linear detector for complex symbols to suppress the co-antenna interference introduced by a multiple input multiple output (MIMO) channel. For generalized MIMO systems, i.e., systems that transmit besides the pure data also complex conjugate repetitions, we show that the standard linear detector has to be replaced by a widely linear (WL) detector. The WL detector consists of four real filters represented by two complex filters for the data symbols and their complex conjugates, respectively. The generalized MIMO transmitter structure allows for a description of the detector that is applicable to many different MIMO systems. Furthermore, we demonstrate that even for systems without complex conjugate repetitions WL filtering is beneficial in iterative detection.