Fading resistance of orthogonal space-time block codes under correlation

In this paper, impact on the bit-error rate performance of orthogonal space-time block codes (O-STBC) due to spatial correlation is investigated. An analytic model for spatial correlation is used which fully accounts for: i) antenna placement and separation and ii) scattering distributions (isotropic, uniform-limited, etc.). We show that the impact of the space is limited on the bit-error rate performance of O-STBC, that is, most of the error rate improvement is due to the 'time-coding' than to 'space-coding'. Further, we investigate how the nonisotropic parameters of an azimuth power distribution, including the angular spread and the mean angle of arrival (AOA) of an impinging signal effect the bit-error rate performance of O-STBC. A rule of thumb for the antenna separation is proposed, where the performance of the O-STBC is optimal under a given scattering environment.