Differential Quasi-Orthogonal Space-Time Block Codes with Full Transmit Diversity

In this paper, we propose a simple differential spacetime block code with a quasi-orthogonal structure, which can offer full rate and full diversity. At the transmitter, we divide the codes into sub-coding blocks, and combine the sub-coding blocks at the receiver to employ differential decoding by channel power estimation instead of decoding each sub-coding block separately. Our general approach can be extended to the recently-proposed quasi-orthogonal codes with full rate and half diversity. Moreover, this scheme is not limited to PSK constellations but can also utilize QAM constellations, so that additional coding gain can be obtained.