Fast sub-optimal detection of quasi-orthogonal space-time block code

In this paper, a fast sub-optimal decoding method is proposed for quasi-orthogonal space-time block codes (QOSTBCs) with four transmit antennas. The proposed method focuses on the phases of received vector to select an origin and create a limited region among proper candidates. The limited region and proper candidates are selected from some sorted lookup tables by utilizing the phases of received vector. Euclidean distance of the most probable candidate is firstly computed and then the distances of other candidates are successively assessed to attain minimum distance. Simulation results confirm that proposed method has adequate performance, while it significantly requires fewer floating point operations compared to the other methods.