Unitary signal constellations for differential space time modulation with more than two transmit antennas

In this paper, we propose new unitary signal constellations for differential unitary space-time modulations (DUSTM) utilizing more than two transmit antennas. DUSTM is a space-time coding scheme which is apt in a continuous varying channel, and in which the channels state information (CSI) are approximately constant over two code block intervals. The proposed unitary designs are constructed from fundamental building blocks which comprise the generator matrices of diagonal cyclic codes, and the 2x2 and 3x3 rotational matrices. The performances of the proposed codes are superior to that of the cyclic codes.