Space time block coding for 4 antennas with coding rate 1

We propose a new space time transmit diversity (STTD) scheme for M (M/spl ges/4) transmit antennas and one receive antenna. The new diversity scheme belongs to the open loop class and consists of an extension to earlier work (see Alamouti, S M., IEEE JSAC, p.1451-8, 1998; Tarokh, V. et al., IEEE Trans. Inform. Theory, vol.45, no.4, p.1456-67, 1999; vol.44, no.2, p.744-65, 1998). The coding rate of the new scheme is one, and, in spite of the presence of intersymbol interference, it achieves, at least, full diversity after applying a multi-dimensional orthonormal rotation to the original constellation. Each sequence with an integer multiple of M received symbols is detected using a maximum likelihood decoding algorithm to get the estimated maximum likelihood sequence.