Integrated MAP detection for V-BLAST systems without channel estimation

Generally, channel estimation is indispensable for signal detection in vertical Bell Laboratories layered space-time (V-BLAST) systems. However, channel estimation always cannot perfectly obtain the channel state information (CSI), and the inaccurate CSI may result in large performance degradation. In this paper, we propose a novel soft V-BLAST detector, called integrated maximum a posteriori (IMAP) detector. Unlike conventional detectors, the IMAP detector can avoid estimating the CSI and directly generate a posteriori probability of data symbols by efficient iterative computations. Moreover, we design a list-based fast searching algorithm to further reduce the complexity of the proposed detector in the cases of large numbers of transmit antennas or high order modulations. Computer simulation shows that the IMAP detector can approximately achieve the performance of the optimal detector using the perfect CSI.