A Trajectory-Driven 3D Non-Stationary mm-Wave MIMO Channel Model for a Single Moving Point Scatterer

Abstract

This paper proposes a new non-stationary three-dimensional (3D) channel model for a physical millimeter wave (mm-Wave) multiple-input multiple-output (MIMO) channel. This MIMO channel model is driven by the trajectory of a moving point scatterer, which allows us to investigate the impact of a single moving point scatterer on the propagation characteristics in an indoor environment. Starting from the time-variant (TV) channel transfer function, the temporal behavior of the proposed non-stationary channel model has been analyzed by studying the TV micro-Doppler characteristics and the TV mean Doppler shift. The proposed channel model has been validated by measurements performed in an indoor environment using a MIMO radar kit operating at 24 GHz. For the measurement campaign, we used a single swinging pendulum as a model for a moving point scatterer. The trajectory of the pendulum has been captured by an inertial measurement unit attached to the pendulum and by a motion capture camera system. The measured trajectories are feed into the proposed mm-Wave MIMO channel model. The results obtained for the micro-Doppler characteristics show an excellent agreement between the proposed MIMO channel model and realworld measured channels in the presence of a moving point scatterer. We believe that our model can serve as a basis for the development of novel non-stationary MIMO channel models capturing the effects caused by moving objects and people.INDEX TERMS MIMO channel, channel measurements, mean Doppler shift, mm-Wave channels, nonstationary channels, multipath propagation, radar, spectrogram, time-frequency analysis.

Interchannel Interference and Mitigation in Distributed MIMO RF Sensing

“…Thus, without any hardware or firmware alteration, there is no known optimal solution to effectively isolate the different RF MIMO channel links. The problem of interference in the Ancortek radar has also been reported by the authors of [37], where they have subtracted the spectrograms to alleviate the interference problem. The solution proposed in [37] is suboptimal and nonrobust; it works when the interference component is smaller than the subchannel's main component and fails when the interference component is of the order of the magnitude of the main component of the subchannel.…”

“…The problem of interference in the Ancortek radar has also been reported by the authors of [37], where they have subtracted the spectrograms to alleviate the interference problem. The solution proposed in [37] is suboptimal and nonrobust; it works when the interference component is smaller than the subchannel's main component and fails when the interference component is of the order of the magnitude of the main component of the subchannel. Therefore, in this paper, we propose an optimal and robust solution that completely eradicates the problem of cross-channel interference.…”

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“…(1) Case With a limited literature search, we found that the spatialtemporal nonstationary characteristics of the nontarget signal channel are very different from those of traditional nonstationary channel models. The existing studies on channel nonstationary characteristics assume the natural scattering characteristic [33] [34]. In contrast, in the RIS coexistence scenario, the nonstationarity of the nontarget signal channel is mainly caused by the unexpected abnormal tuning of the RIS.…”

Reconfigurable Intelligent Surfaces for 6G: Applications, Challenges and Solutions

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