Multiple symbol double differential space-time coded OFDM

Recently space-time coding (STC) has received increasing attention because of its ability to combat fading effect. Among existing schemes, double differential space-time coding is of special interest because its decoding process does not require channel state information. Furthermore, it is applicable to continuous fast time varying channels. Our article focuses on the improvement of double differential space-time coding by considering multiple symbol decoding. We develop a trellis-based decoding algorithm for multiple symbol double differential space-time coding, derive the branch metric, and validate the improvement via simulations. However, the performance of this scheme degrades considerably in frequency selective channels. Another focus of this article is to construct suitable model in which OFDM can be concatenated with multiple symbol double differential space-time coding.