Performance analysis of a mimo-OFDM wireless link with space-time block code (STBC)

Abstract

The demand for high-speed mobile wireless communications is rapidly growing. OFDM technology promises to be a key technique for achieving the high data capacity and spectral efticiency requrements for wireless communication systems of the ncar futrure. Because of the demand of higher transmission data rate and better transmission quality, the MIMO-OFDM technology is the trend of the next-generation WLANs and wireless communication. In this thesis. we evaluate the bit error rate performance of a MIMO-OFDM wireless link with STBC. Analysis is also extended to evaluate the performance improvement due to application of convolutional coding. Theoretical analysis is carried out to evaluate the impact of time selective fading. timingjitter. Doppler shift. multiplicative fading and AWGN on OFDM systems with DQPSK. QI'SK and DI'SK modulation .. The performances of OFDM system in Rayleigh and Rician fading channels are evaluated with different values of fading and jitter variances. The 13ER performance of a quisi-orthogonal STBC-OFOM with multiple transmitting and singlc receiving antennas are analytically developed. The analysis is extended for a MIMO-OFDM system without and with convolutional coding for combining multiple receiving antennas. which offers significant improvement in the system performance. 13ER performance results of space-time block coded (STBC) system are determined for different antenna configuration using MATLAB. The results show that the reliability of the wireless link increases as the number of transmits and received antenna increase with the use of coding. The performance results also reveal that DQI'SK system suffers least degradadtion in BER performance and minimum power penalty due to the effect of timing jitter and variances compared to other modulation formats. Significant improvement in 13ER performance in terms of coding gain is also observed due to coding.