Performance Evaluation of Diversity Schemes over Space-Polarization MIMO Channels

We compare the performance of orthogonal space-time block code (OSTBC) diversity schemes for co-polarized (CP) MIMO architectures and for space-polarization MIMO (SP-MIMO) architectures. This latter architecture employs a dual-polarized antenna in place of the co-polarized antennas to provides twice the number of antenna ports without substantially increasing the form factor of the antenna system. However, SP-MIMO systems exhibit power asymmetries in the MIMO sub channel gains due to the use of orthogonally-polarized antennas. We derive an approximate outage capacity formulation for a SP-MIMO 1-path narrowband MIMO model and provide finite-SNR diversity-multiplexing trade off of OSTBC schemes over such SP-MIMO channels. We show that SP-MIMO systems outperform CP-MIMO. Also, the so called "diversity order" definition used in literature for Rician MIMO channel is shown not be a valid benchmark to compare performance of SP-MIMO and CP-MIMO under the considered channel normalization approach.