The foundation of the ideas in this paper dates back to the 1980s, with investigations about the locus and properties of sensor array manifolds to find out the specifications of arrival plane wave signals. In its expansion, it has been brought forward for the fifth-generation (5G) millimeter (mm)-wave systems. The main topic of the paper is an antenna array manifold vector-based multibeam, spatiotemporal, super-resolution, beamforming framework for the prospective crowded mm-wave multiple-input multiple-output (MIMO) channel communication of 5G networks.

The paper criticizes the traditional view and utilization of the MIMO channel models, which have been called “non-parametric”; for channel modeling, the paper announces a family of “parametric” models. Operational frequency, Tx and Rx array geometry, number of multipaths, their directions, relative path delay, Doppler frequency shift coefficient, and complex path finding coefficients are the main factors in the parametric modeling under discussion. Blind channel estimation is used instead of a traditional pilot-based model.

The technical discussion starts with the MIMO communication system model. Therein, a multiuser scenario in which the receiver and transmitters are armed with multiantenna equipment is discussed. To model the transmitter, a set of orthogonal subcarriers is considered; periodically, unique pseudonoise (PN) codes are deployed by any co-channel users, modulated based on frequency offset. At a time instance, the main lobe is steered by a weighted matrix toward the favorite user. Next, an antenna array manifold for the receiver is formulated and the base-band signal of the receiver antenna is modeled. In the receiver modeling, the concept of the array manifold is extended to the Doppler-spatiotemporal manifold vector to reflect and process the intersymbol interference, multiaccess interference, and noise effects. The performance bounds are compared with the Cramér–Rao bound. Next, a novel spatiotemporal beam-former for the mm-wave communication system is proposed. Finally, computer simulation studies are provided that demonstrate the meaningful superiority of the presented technology compared to traditional MIMO systems.

The paper is a high-tech and high-class MIMO study. Its ideas have been constructed based on reliable and robust methods of array antenna manifold theory and its extension, which undoubtedly is useful and strong enough for any concerned discussions. The structure of the model for the receiver seems somehow heavy; in these platforms, tiny, light receivers are favored.