Multi-Layer Multi-User MIMO with Cylindrical Arrays under 3GPP 3D Channel Model for B5G/6G Networks

Massive MIMO technology has significantly enhanced the performance of 5G networks, and its potential is poised for further expansion in the upcoming 6G standard. Large antenna arrays at the transmitter, combined with multiple antennas at each user can enable multi-user multi-layer MIMO data transmission. In this paper, we study the potential benefits of a cylindrical array arrangement in a 3D scenario, compared to the conventional trisector planar array configuration. In fact, cylindrical arrays allow for more uniform coverage of the cell, don't suffer from beam broadening, and can mitigate the sector-edge problem. For this purpose, we assess the effectiveness of multi-user and multi-layer precoding and combining strategies using cylindrical arrays outfitted with both single and dual-polarized antenna elements, under the most recent 3GPP-compliant 3D channel model for 5G, and by taking into account impairments due to an imperfect channel estimation. Results and comparisons with planar arrays in terms of sum-rate, spectral efficiency and outage are provided for outdoor Line-of-Sight (LOS), outdoor Non-LOS, and indoor users. They highlight the benefits of using cylindrical arrays in realistic 3D scenarios, even when the planar arrays of the different sectors are coordinated to operate as a single array. This makes them an interesting solution for next-generation 6G networks.