Physics

Channel (broadcasting)

MIMO

Multi-user MIMO

Optics

Spatial correlation

Engineering

Wavefront

Spectral density

Precoding

Electronic engineering

Computer science

Telecommunications

Channel capacity

IEEE Transactions on Vehicular Technology

Ultra-massive multiple-input multiple-output (MIMO) technology will bring unique channel characteristics that need to be fully explored through channel measurements and channel modeling. In this paper, single-user and multi-user channel measurements using ultra-massive MIMO antenna arrays with different configurations are conducted at 5.3 GHz band. The non-stationarity, spherical wavefront, channel hardening, and sparse properties are validated by the channel measurements. Correspondingly, a general three-dimensional (3D) sixth generation (6G) non-stationary geometry-based stochastic model (GBSM) for ultra-massive MIMO communication systems is proposed. The statistical properties of channel measurements and the corresponding channel model are studied, including delay power spectral density (PSD), angular PSD, spatial cross-correlation function (SCCF), normalized user-side correlation matrix, singular value spread (SVS), degrees of freedom (DoF), and diversity level. In addition, channel capacities of channel measurements and the corresponding channel model are studied. The accuracy of the proposed general channel model is validated by the consistency of simulation results and measurement results, which indicates that the proposed model can be applied to ultra-massive MIMO communication systems.

Ultra-Massive MIMO Channel Measurements at 5.3 GHz and a General 6G Channel Model