A modified Alamouti scheme for frequency selective channels incorporating turbo equalization

The Alamouti scheme can achieve transmit diversity in the presence of frequency selective flat fading channels. The technique has received considerable attention mainly because of its processing simplicity. Recently, a modification to the Alamouti scheme to achieve transmit diversity in the presence of frequency selective fading channels was proposed. This modified scheme requires parallel equalization of the transmitted information blocks. In this paper a turbo equalization system is proposed that requires the same number of component equalizers but offers improved system BER performance. The idea treats a pair of frequency selective channels as a parallel-concatenated turbo encoder.