This paper presents a new double space-time transmit diversity (DSTTD) transceiver exploiting the special structure of the channel matrix. This accounts for accomplishing very low complexity maximum-likelihood (ML) detector. First, the proposed ML detector requires significantly fewer computations than that of the Schnorr-Euchner sphere decoding (SE-SD) algorithm in respective of both the worst-case and the average complexity. Moreover, the complexity of the proposed ML detector is further reduced with sacrificing slight performance loss, provided that the proposed DSTTD transmitter is used.