Space time coding schemes for 4 or more antennas

We present a new space time transmit diversity (STTD) scheme for 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 the work presented by Alamouti (1998) and by Tarokh et al. (1998, 1999). Another hybrid scheme that combines open and close loop classes is also presented. The coding rate of the new scheme is one and in spite of the presence of intersymbol interference it may achieve the full diversity after applying a multi-dimensional orthonormal rotation to the original constellation. For each coding scheme every block with 8 received symbols is detected using a maximum likelihood decoding algorithm to get the estimated maximum likelihood sequence. Q-QAM modulations are analysed.