Two Quasi Orthogonal Space-Time Block Codes with Better Performance and   Low Complexity Decoder
  This paper presents two new space time block codes (STBCs) with quasi orthogonal structure for an open loop multi-input single-output (MISO) systems. These two codes have been designed to transmit from three or four antennas at the transmitter and be given to one antenna at the receiver. First, the proposed codes are introduced and their structures are investigated. This is followed by the demonstration of how the decoder decodes half of transmitted symbols independent of the other half. The last part of this paper discusses the simulation results, makes performance comparison against other popular approaches and concludes that the proposed solutions offer superiority. 
Ali Lotfi-Rezaabad, Siamak Talebi, and Ata Chizari
cs.IT math.IT