A Novel Method for Enhanced Quasi-Orthogonal Space Time Block Codes in Wireless Communication
A complex orthogonal design that provides full diversity and full transmission rate for a space - time block code is not possible for more than two antennas. The authors design rate one codes which are quasi-orthogonal and provide partial diversity. The decoder of the proposed codes works with pairs of transmitted symbols instead of single symbols. A number of Quasi-Orthogonal Space-Time Block Codes (QOSTBC) has been proposed for using in multiple transmit antennas systems. In this paper, based on circulant matrix, they propose a novel method of extending any QOSTBC constructed for 4 transmit antennas to a closed-loop scheme.