Abstract: It is well known that it is impossible for complex orthogonal space-time block codes with full diversity and full rate to have more than two transmit antennas while non-orthogonal designs will lose the simplicity of maximum likelihood decoding at receivers. In this paper, we propose a new quasi-orthogonal space-time block code . The code is quasi-orthogonal and can reduce the decoding complexity significantly by employing zero-forced and minimum mean squared error criteria. This paper also presents simulation results of two examples with three and four transmit antennas respectively.

Key words: diversity; ML; MMSE, MIMO; QOSTBC; ZF