Selection of channel update frequency for digital fading simulation using spatial channel model

As MIMO and smart antenna technologies are feasible, modeling a spatio-temporal channel at the system level is getting crucial for the purpose of evaluating multi-antenna techniques. Since the proposed spatial channel model (SCM) is complex and time consuming, it needs to be simplified to run MIMO system simulations within a reasonable time period. One of the time-saving methods in digital simulation is to repeatedly use channel coefficients generated by the SCM for a reasonable duration. The repeated use of channel coefficients is based on the fact that the characteristics of sampled and repeated fading follows that of Rayleigh fading. In this paper, the channel updated frequency calculation method for digital simulation is proposed, which minimizes BER degradation in environments with different mobile speeds and different spatial parameters such as angle spread (AS), direction of travel (DoT) and angle of arrival (AoA). Since all multipaths in the SCM are mutually independent random processes, the channel updated frequency can be applied all multipaths for MIMO channel simulations.