Códigos de Bloco Espaço-Tempo Diagonais 2 × 2 com Boas Densidades Normalizadas

In this work we prove that the diagonal space-time block code 2 × 2 with minimum determinant 1 based on an irreducible quadratic polynomial x^2+ζ_3-1 over Q(ζ_3) is optimal in terms of normalized density. We also present diagonal space-time block codes 2 × 2 with minimum determinant 1 based on irreducible quadratic polynomials over Q( √ d), d = −2, −7 that have good normalized densities.