Hybrid BLAST Space-Time Block Code for MIMO Communication Systems

Abstract

The hottest issue of next generation communication systems is data throughput improvement for any wireless channel conditions. MIMO systems are the key techniques for the next generation communication systems. BLAST system achieves high data rates with acceptable BER performance over a good channels state while STBC system can achieve better BER performance even for a bad-state channel but with lower data rate than BLAST. Hybrid BLAST-STBC system is the effective solution to achieve a good tradeoff between STBC and BLAST systems since it improves the BER performance and keep them robust over a bad MIMO channel state compared with the conventional BLAST system. Adaptive switching system is used in order to choose the best transmit or receive scheme for some channel state. When the channel state is known at both the transmitter and the receiver, the receiver informs the transmitter through a feedback link which transmission scheme is to be used. This thesis will study and compare the BER performance and capacity of hybrid BLAST-STBC systems at ML receiver with BLAST and STBC systems. The effect of a transmit link deep fading in 4 × 4 BLAST, hybrid BLAST-STBC and STBC will also be comparatively studied . At every possible case of transmit link deep fading, the best throughput system in each case is determined. Thereby, an adaptive switching hybrid 4 × 4 MIMO system is proposed and tested where the results stated that this system achieves the best throughput for any deep fading case. MATLAB software has been used as the main platform for system simulation.