Exploiting the structure of OSTBC´s to improve the robustness of worst-case optimization based linear multi-user MIMO receivers

In this paper, we improve the performance of robust linear receivers for multi-user multiple-input multiple-output (MIMO) wireless systems by exploiting the inherent structure of orthogonal space-time block codes (OSTBC). This particular structure results in a worst-case optimization problem with structured uncertainty set. Exploiting this structure, an improved robust linear receiver with a combination of fixed diagonal loading and adaptive non-diagonal loading of the data covariance matrix is obtained.