New Delay Optimum Quasi-Othogonal Space-Time Block Codes with Full Spatial Diversity

In this paper, we propose a novel, systematic structure for quasi-orthogonal space-time block codes (QO-STBCs) achieving full rate for even number of transmit antennas over quasi-static Rayleigh fading channels. Especially, the new codes are delay optimal unlike conventional QO-STBCs and thus have a great advantage in ML decoding complexity at a receiver. In order to exploit full spatial diversity, we utilize a constellation rotation method and also examine optimal rotation angles through brute-force search for some cases of modulations and transmit antennas. Computer simulation results show that the proposed codes exhibit average error performance almost the same as or better than the existing QO-STBCs.