Increased diversity space-time coding using the diversity transform

The paper presents a method for constructing space-time block codes for multiple-input multiple-output channels by concatenating orthogonal designs with the so-called diversity transform. Relying on unitary transforms, the diversity transform increases the channel alphabet without sacrificing information rate, bandwidth, or Euclidean distance. The distribution of the resulting channel alphabet is shown to quickly become Gaussian-like. Specific code matrices are constructed and optimized based on the cutoff rate. Both optimum and, reduced-complexity, suboptimum detection algorithms are presented. Simulation results are provided for demonstrating the gains attainable when using the proposed codes.