Computational Complexity of Decoding Orthogonal Space-Time Block Codes

The computational complexity of optimum decoding for an orthogonal space-time block code G_N satisfying G_N^HG_N = c(Σ_k=1^K |s_k|²)I_N 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, 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.