A Note on Discrete-Time Triply-Selective MIMO Rayleigh Fading Channel Models

We discuss recent results on discrete-time models for triply-selective multiple-input multiple-output (MIMO) Rayleigh fading channels. Our key finding is that a previously proposed model (Xiao et al., 2004), which allows for efficient computer simulations, is sufficiently accurate for a wide range of practical scenarios.

IN digital mobile communication systems, baseband signal processing is typically carried out in the discrete-time domain. Correspondingly, an end-to-end discrete-time channel model comprising the continuous-time physical channel model, the (analog) transmit and receive filters, as well as the sampling process at the receiver is of great interest. In [1], a statistical discrete-time model for single-input single-output (SISO) wide-sense stationary (WSS) Rayleigh fading channels with uncorrelated scattering (US) and selectivity in time and frequency was proposed. This model was later extended in [2] to MIMO WSSUS Rayleigh fading channels with selectivity in time, frequency, and space. It was concluded in [2] that the correlations between channel coefficients of the discrete-time MIMO channel model can be written as the product of temporal correlation, inter-tap correlation, and spatial correlations. This property enables computationally efficient computer simulations on MIMO triply selective channel fading.