Fading-Resilient Super-Orthogonal Space-Time Signal Sets: Can Good Constellations Survive in Fading?

TL;DR

This paper introduces super-orthogonal codes that expand orthogonal designs to enhance coding and diversity gains, analyzing their robustness in fading channels and conditions for shape preservation at the channel output.

Contribution

It defines discernible constellation expansions for orthogonal designs, introduces super-orthogonal codes, and derives conditions for their shape preservation in fading channels.

Findings

Super-orthogonal codes enable additional coding gains.

Channel preserves relative distances and angles of expanded constellations.

Conditions for shape preservation are established.

Abstract

In this correspondence, first-tier indirect (direct) discernible constellation expansions are defined for generalized orthogonal designs. The expanded signal constellation, leading to so-called super-orthogonal codes, allows the achievement of coding gains in addition to diversity gains enabled by orthogonal designs. Conditions that allow the shape of an expanded multidimensional constellation to be preserved at the channel output, on an instantaneous basis, are derived. It is further shown that, for such constellations, the channel alters neither the relative distances nor the angles between signal points in the expanded signal constellation.