Computational Complexity of Decoding Orthogonal Space-Time Block Codes

TL;DR

This paper analyzes the computational complexity of optimal decoding for orthogonal space-time block codes, providing equivalent decoding techniques, modifications for special cases, and unifying previous results in the literature.

Contribution

It quantifies the decoding complexity for orthogonal space-time block codes and extends existing results to cases where the constant c exceeds 1.

Findings

Four equivalent decoding techniques with same complexity

Modified formulations for special cases with examples

Unified and extended previous literature results

Abstract

The computational complexity of optimum decoding for an orthogonal space-time block code G satisfying the orthogonality property that the Hermitian transpose of G multiplied by G is equal to a constant c times the sum of the squared symbols of the code times an identity matrix, where c is a positive integer is quantified. Four equivalent techniques of optimum decoding which have the same computational complexity are specified. Modifications to the basic formulation in special cases are calculated and illustrated by means of examples. This paper corrects and extends [1],[2], and unifies them with the results from the literature. In addition, a number of results from the literature are extended to the case c > 1.