Improved Superorthogonal Codes Through Generalized Rotations

Abstract—Concatenation of orthogonal space–time block codes (OSTBC) with an outer trellis has led to simple and powerful codes, known as superorthogonal codes or space–time block trellis-coded modulation. In this letter, we generalize these codes by finding new code supersets and corresponding set partitioning, resulting in improved coding gain. We provide design guidelines for the labeling of the generalized code trellises and demonstrate the gains by several example designs for two and four transmit antennas. Index Terms—Multiple-input multiple-output (MIMO), spacetime coding, superorthogonal codes. I