Single-carrier (SC) block transmission with cyclic prefix (CP) is a method with several advantages that has been incorporated into standards. This paper has analyzed the performance of multi-antenna SC-FDE under Alamouti signaling and cyclic-delay diversity (CDD). Our analysis shows that the characteristic of diversity it is depends on data block length and data transmission rate as well as on the channel memory and antenna configuration. At higher rates their diversity diminishes and full diversity is available to both CDD and Alamouti signalling below a certain rate threshold. From our investigation we say that at high rates Alamouti signalling provides twice the diversity of SISO SC-FDE, while the diversity of the SISO SC-FDE under the CDD diversity degenerates. In this paper, we analyze the performance of SC-FDE in conjunction with either cyclic delay diversity (CDD) or Alamouti signaling, fully characterizing the diversity as a function of transmission-block length, number of antennas data rate and channel memory. In the process, we obtain a threshold rate (as a function of data-block length, channel memory, and number of antennas) below which the full spatial-temporal diversity is achieved, while at higher rates the diversity of both schemes diminishes. Our analysis shows that at high rates Alamouti signaling provides twice the diversity of SISO SCFDE, while the CDD diversity degenerates to the diversity of the SISO SC-FDE.