BER Analysis of MIMO-OFDM System using STBC and V-BLAST

Abstract

Orthogonal Frequency-Division Multiplexing (OFDM) divides a single information stream into several closely spaced narrowband sub channel frequencies, reduces interference in the system, and allows for more bandwidth of data. The wireless technology called Multiple Input-Multiple Output (MIMO), applies more than one sending and receiving antennas. MIMO boosts capacity of data in wireless communication systems. The same data is delivered across several antennas with same path and in the same bandwidth in a MIMO system. For 4G and 5G broadband wireless communications, MIMO with FDM is the most best air interface. It has the best spectral efficiency, large data capacity and high data throughput. If space-time coding methods are used along with many sending and receiving antennas, that increases data rate over wireless channels. Hence it is possible to obtain the capacity limit of Shannon Theorem. Vertical - Bell Laboratories Layered Space-Time (V-BLAS T) algorithm is applied to reduce the interference caused by multiple paths of data. Before assigning a symbol to each sub stream’s bit, the signal is demultiplexed. The Space-Time-Block Coding (STBC) is another technique, used for wireless communications for the betterment of MIMO with OFDM. STBC is suitable for the system with more than one antenna for sending and receiving. STBC exploits different versions of data and increase data transfer reliability. The performance of MIMO-OFDM system with respect to Bit Error Rate (BER) is examined in this work. Two antennas are used for sending and two for receiving data. Two algorithms STBC and VBLAST are applied to the above communication system. Three detection techniques namely Zero-Forcing (ZF), Minimum-Mean Square Error (MMSE), and Maximum Likelihood (ML) are applied to V-BLAST-MIMO-OFDM, and their BER performance is compared. Finally, the BER comparison of VBLAST and STBC is done. Simulation results are obtained using Matlab2020A. The results obtained for MIMO-OFDM system through simulation give better BER performance with ZF, ML, MMSE. The simulation findings show that the MIMO-OFDM system using VBLAST performs better than STBC. The application of V-BLAST technique to the MIMO-OFDM with detection techniques has further improved the BER performance. The simulation findings also show that V-BLAST with ZF and MMSE has improved the BER performance with BER drop of 76.13 and 87.11 percent respectively. V-BLAST with ML produces best overall BER performance with a BER drop of 94.85 percent.