Massive MIMO Propagation Modeling With User-Induced Coupling Effects Using Ray-Tracing and FDTD

Abstract

The article describes a numerical approach for Massive MIMO channel modeling that accounts for the effects of electromagnetic coupling between a user and the receiving device. The modeling is performed by a combination of the Finite-Difference Time-Domain and the Ray-Tracing methods, supplemented with a stochastic geometry model of the propagation environment. The influence of user-coupling on the channel properties was studied statistically using the singular value spread and matrix power ratio metrics of the channel correlation matrix. The time-averaged Poynting vector distribution in the near-field of the receiver was evaluated using a realistic human phantom model and the Maximum Ratio Transmission precoding scheme in the downlink. The average enhancement of the timeaverage Poynting vector magnitude at the receiver location, compared to the surrounding area, was found to be around 10 dB when using 36 antenna elements at the base station. The electromagnetic field exposure of the phantom was assessed in terms of the 10g-average peak-spatial Specific Absorption Rate and compared with the existing public guidelines. Comparison of the EMF and exposure results provides a new perspective on the future regulatory procedures.

5G NR FR2 Femtocell Coverage Map Using an Omnidirectional Twisted SWAA

“…Finally, Table II presents a comparison among related works on 5G channel investigations. S. Shikhantsov, in [19], has proposed a numerical approach for Massive MIMO channel using a combination of the Finite-Difference Time-Domain (FDTD) and the Ray-Tracing methods. The references [20] and [21] report experimental path loss-based propagation analyses using continuous waves (CW) in outdoor vegetated suburban areas and indoor environment, respectively.…”

“…Most papers on wireless propagation are concerning the propagation coefficient estimation and/or channel modeling, from experimental campaigns based on commercial antennas and ray tracing-based approaches [19][20][21][22]. Completely, the current manuscript reports the implementation and coverage map estimation of an indoor femtocell based on the new 5G NR standard [4] operating in FR2.…”

A Stochastic Geometry Approach to EMF Exposure Modeling

“…Electromagnetic field (EMF) exposure due to cellular networks is classically evaluated empirically either through insitu measurements [1], drive-tests [2], [3] or sensor networks [4]. Numerically, this evaluation, either by using raylaunching softwares [5], ray-tracing softwares [6] or other simulation methods based on propagation models [7]- [9], is however difficult to obtain deterministically in a reasonable time. It is also subject to many uncertainties (due to the number of base stations in operation, the environment geometry, the presence of people and vehicles causing shadowing...).…”

Spatial Correlation in Indoor Massive MIMO: Measurements and Ray Tracing

“…From these results, we estimate the hotspot crosssection radius to be around 0.3 m, or 3 wavelengths at 2.6 GHz and 1.6 m Tx-Rx separation distance. In [7], [8] the hotspot power density distribution was modeled as an interference pattern of a large number of plane-waves incident at the Rx. The host-spot size was around 1 wavelength (86 mm) at 3.5 GHz.…”