Performance of Multi-Stratum Space-Time Coding for N_r x 2 MIMO Channels

V-BLAST is a common architecture for transmitting multiple coded data streams over a MIMO channel. A drawback of V-BLAST, however, is that it offers little diversity. Multi-stratum space-time coding has been proposed as a generalization of V-BLAST, where the multiple transmitted data streams are first separately modulated using an orthogonal space-time block code and then are superimposed and transmitted over the multiple antennas. In this work, the performance of multi-stratum space-time coding for N_r × 2 MIMO channels is analyzed, where the two superimposed streams are Alamouti modulated and coded at a rate optimized for the SNR. It is shown that the scheme offers significant improvement in terms of diversity while the encoding/decoding complexity remains essentially unchanged.