Soft MMSE receiver for turbo coded MIMO system

In this paper, we propose a simple and efficient soft detection scheme for turbo coded multi-input multi-output (MIMO) system using minimum mean square error (MMSE) scheme. Although the maximum performance can be achieved using a maximum likelihood (ML) soft detection scheme, the complexity increases exponentially by the number of antennas and modulation orders. In this paper, we divide the soft detection process into three separate sequential problems. In combination with turbo codes, the proposed soft MMSE scheme produces comparable performance to ML detection with drastically reduced complexity.