Alamouti Code Assisted V-BLAST (ACAV): A New Space-Time Architecture

We present Alamouti code assisted V-BLAST (ACAV), a new space-time architecture for fading multiple- input multiple-output (MIMO) channels. The transmission design is simple and flexible: two antennas are used to transmit signals the same as Alamouti code, while the other antennas are used to transmit signals similar to the popular V-BLAST. For maximum-likelihood decoding, the analysis shows that ACAV can achieve a certain coding gain over V-BLAST. To reduce the receiver complexity, the (ordered) successive interference cancellation decoding is introduced: the receiver first decodes the two data streams related to Alamouti code, and then decode the other data streams successively. The estimation for the first two decoded data streams is reliable enough to decrease the error propagation to the next decoding stages, resulting in much higher diversity order and lower symbol error rate with about the same computational complexity compared to V-BLAST. The simulation results reveal that ACAV significantly outperforms V-BLAST.