STBC-VBLAST for MIMO wireless communication systems

The vertical Bell-labs layered space-time (VBLAST) scheme can be used to exploit the capacity potential provided by multiple transmit antenna systems. In VBLAST systems, detection and decoding are performed layer by layer in a successive way. However, successive processing degrades performance because of the low minimum diversity and error propagation. In this paper, we propose a new STBC-VBLAST scheme, which integrates G orthogonal n×m space-time block codes (STBC) into the lower layers of VBLAST systems with n_T transmit and n_R receive antennas. The remaining higher layers transmit independent data streams. At the receiver, low-complexity detection with modified sorted QR decomposition (SQRD) and successive interference cancellation is used. With STBC-VBLAST, the minimum diversity d among all the layers is the smaller of n(n_R-n_T) + n² and n_R-n_T +Gn + 1, which is generally larger than that for other VBLAST systems. Noting that the performance improvement is accompanied by a partial loss in spectral efficiency, we also indicate how to choose G to get good performance while using bandwidth efficiently.