Channel Coded STBC-OFDM based Transmit Diversity Systems in Multipath Rayleigh-Fading Channels

In this paper, a channel coded space-time block coded orthogonal frequency division multiplexing (STBC-OFDM) system using Alamouti coding scheme is proposed and their performance is compared in terms of bit error rate (BER) with the existing STBC-OFDM system. The system has been investigated using various modulation techniques such as BPSK, QPSK, 16-PSK and 4-QAM. For channel coding technique, the convolutional encoder is used at the transmitter and the Viterbi decoder is used at the receiver. Simulation results shows the advantage of combining the channel coding with the STBC-OFDM system. It is shown that channel coded STBC-OFDM system has a better BER performance over the conventional system. The proposed system achieves a coding gain (CG) of over 6.0 dB in multipath Rayleigh-fading channel.