Performance Analysis of OFDM-OSTBC system under Various Fading Channels using Different Doppler Spectra

The era of wireless communication is rapidly increasing in our day-to-day lives. The main aim of 4G wireless systems is to provide users with high speed and high performance in different channel conditions. 4G systems support interactive multimedia, voice, streaming video, internet and other broad band services. 4G is a IP based mobile system with high speed, high capacity and low cost per bit. Orthogonal Frequency Division multiplexing (OFDM) is one of the most promising techniques to meet the challenges. A Multiple-Input-Multiple-Output (MIMO) system utilizes multiple number of antennas both at transmitter and receiver. This paper presents the performance of OFDM-OSTBC system under various fading channels using different Doppler spectra. Simulation results shows that for two transmitting antennas and one receiving antenna the Bit Error Rate (BER) for OFDM-OSTBC system is observed to be 0.03919 at SNR 6dB and for three transmitting antennas and two receiving antennas the Bit Error Rate (BER) for OFDM-OSTBC system is observed to be 0.0013 at same SNR. It has been observed that BER is low for flat Doppler spectrum. Hence by using MIMO system ie., by implementing both transmit and receive diversity bit error rate (BER) is reduced. With reduced Bit Error Rate (BER), it is possible to achieve high bit rate.