Performance of differential quasi-orthogonal space-time block coded cellular system in the presence of interference

In this paper, we propose a simple differential quasi-orthogonal space-time block code, which can offer full rate and full diversity. At the transmitter end, we divide the codes into sub-coding blocks, and combine the sub-coding blocks into one at the receiver to employ differential decoding by channel power estimation instead of decoding each sub-coding block at first hand. Our general approach can be extended to the recent 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. We first examine our work in an individual link with fixed position without the presence of co-channel interference. Then, we investigate the performance in MIMO cellular systems.