Quasi-Orthogonal Space-Time Block Codes for Data Transmission over Four and Eight Transmit Antennas with Very Low Feedback Rate

Since the publication of Alamouti’s famous space-time block code for two transmit antennas, various suboptimal space-time block codes for multi-input/multi-output fading channels have been proposed not achieving full diversity at full rate. In this paper we present a family of adaptive, channel dependent, rate-one Extended Alamouti spacetime block codes for four and eight transmit antennas. Only partial channel state information is sent back from the receiver to the transmitter. Transmit diversity is improved up to nearly the optimum diversity value. This high diversity can be exploited with zero forcing receiver as well as with maximum-likelihood (ML) receiver.