El Gamal, H.Aktas, D.Damen, M. O.2016-02-082016-02-082005-060018-9448http://hdl.handle.net/11693/24027The design of space-time signals for noncoherent block-fading channels where the channel state information is not known a priori at the transmitter and the receiver is considered. In particular, a new algebraic formulation for the diversity advantage design criterion is developed. The new criterion encompasses, as a special case, the well-known diversity advantage for unitary space-time signals and, more importantly, applies to arbitrary signaling schemes and arbitrary channel distributions. This criterion is used to establish the optimal diversity-versus-rate tradeoff for training based schemes in block-fading channels. Our results are then specialized to the class of affine space-time signals which allows for a low complexity decoder. Within this class, space-time constellations based on the threaded algebraic space-time (TAST) architecture are considered. These constellations achieve the optimal diversity-versus-rate tradeoff over noncoherent block-fading channels and outperform previously proposed codes in the considered scenarios as demonstrated by the numerical results. Using the analytical and numerical results developed in this paper, nonunitary space-time codes are argued to offer certain advantages in block-fading channels where the appropriate use of coherent space-time codes is shown to offer a very efficient solution to the noncoherent space-time communication paradigm.EnglishDiversity-versus-rate tradeoffGeneralized likelihood ratio test (GLRT) receiversNoncoherent channelsSpace-time codingCommunication channels (information theory)Diversity receptionEncoding (symbols)Fading (radio)Matrix algebraNumerical methodsOptimizationSignal receiversTransmittersDiversity versus rate tradeoffGeneralized likelihood ratio test (GLRT) receiversNoncoherent channelsSpace time codingInformation theoryArticle10.1109/TIT.2005.850139