A space-time model for frequency nonselective Rayleigh fading channels with applications

This paper expands the model of the TDMA wireless fading process at the mobile station to explore the fading process at the base station and derives a space-time cross-correlation between two antennas on the frequency nonselective Rayleigh fading channel. The model may be employed in transmitting or receiving schemes that utilize multiple antennas. Its application in effecting receiver diversity is demonstrated by predicting required antenna separation for a given level of performance. It is shown that once the optimal antenna separation is achieved for a given geometric parameter set, the performance does not change much by increasing the antenna separation further. The properties of the cross-correlation with respect to the variation of geometric parameters, which include the scatterer ring size and the mobile position, are examined by investigating the analytical bit error performance of binary phase shift keying (BPSK) modulation under the perfect channel state information (CSI) assumption.