Recently it is well known that MIMO (multi-input multi-output) systems are superior to SISO (single input single output) systems for performance. So, there are many researches for MIMO systems. Among these researches TD (transmit diversity) and spatial multiplexing techniques are worthy of notice.
Since the STBC (space-time block codes) gets the TD by using diversified space (antenna) and time, we obtain the high BER (bit error rate) performance. On the other hand, the V-BLAST (vertical Bell laboratories layered space time) offers high data rate by using the channel capacity enhanced from multiple antennas. The multiple STBC system with V-BLAST detection has some TD as well as some spatial multiplexing effects.
In this thesis, we consider assigning STBC signals to transmit antennas to enhance the performance of multiple 2×2 STBC system. The assignment is considered in multiple STBC systems firstly. We propose the optimal assignment based on the min-max sense with V-BLAST detection. Simulation results show that our proposed system presents the improved performance in BER by assigning STBC signals to transmit antennas. In addition, we propose a suboptimal method by regarding the V-BLAST detection as the linear detection for reducing the computational complexity and obtain the performance similar to the optimal method.
