Degrees of Freedom of Ray-Based Models for mm-Wave Wideband MIMO-OFDM

Abstract

In this paper we analyze the number of degrees of freedom needed to accurately capture and model wideband MIMO-OFDM channels. Two modeling approaches are considered, either examining each coefficient of the conventional inputoutput MIMO channel matrix or investigating the components constituting the physical ray-based propagation between the antenna arrays. As our analysis accounts for wideband channels, a time domain decomposition of MIMO channels into tapped delay lines is performed in each case. The efficiency of each approach is then evaluated in terms of number of taps to determine the most appropriate representation between either the conventional antenna-based one or the propagation-based one. This analysis is performed analytically using the Saleh-Valenzuela model which is recognized for its consistency for wideband as well as spatial modeling. We exploit the second-order statistics of the Channel Impulse Response to derive the taps weights.

A Critical Review on Channel Modeling: Implementations, Challenges and Applications

“…Saleh-Valenzuela Channel Modeling: The SV model is widely used to assess the system performance under the assumption of channel bandwidth when it is quite large (500 MHz). In the SV model, the total numbers of signals are assumed to pursue the Poisson distribution, and the signals with certain delays inside the cluster can be determined due to the large time resolution [190]. The IEEE WPAN has already appraised the SV model in its standards [190,191].…”

“…In the SV model, the total numbers of signals are assumed to pursue the Poisson distribution, and the signals with certain delays inside the cluster can be determined due to the large time resolution [190]. The IEEE WPAN has already appraised the SV model in its standards [190,191]. To practice the massive MIMO and mmWave scenarios in 5G systems, the on-going SV model needs to be upgraded.…”