Engineering

3G MIMO

MIMO

Bandwidth (computing)

Materials science

Graphene

Telecommunications

Computer science

Spatial multiplexing

Beamforming

Path loss

Physics

Wideband

Nanotechnology

Multiplexing

Terahertz radiation

Electronic engineering

Transmission (telecommunications)

Channel (broadcasting)

Wireless

Multi-user MIMO

Channel capacity

Optoelectronics

Terahertz (THz)-band communication (0.1-10 THz) is envisioned as a key wireless technology to satisfy the in- creasing demand for faster data-rates in beyond 5G systems, thanks to its ultra-broad bandwidth. The very high path loss at THz frequencies and the limited transmission power of THz transceivers impose a major distance limitation for THz wireless communications. To increase the communication distance and the achievable data rates at THz-band frequencies, the concept of Ultra-Massive MIMO (UM-MIMO) has been introduced, which integrates a very large number of nano-antennas (e.g., 1024) in very small footprints (e.g., 1 mm^2). In this paper, an end-to-end model for UM-MIMO communication in the THz band is developed, by accounting for the properties of graphene- based plasmonic nano-antenna arrays and the peculiarities of three- dimensional THz propagation. The developed model is utilized to investigate the performance of the UM- MIMO channel. In particular, the path gain, the array factor and the the wideband capacity for both spatial multiplexing and beamforming regimes are analyzed. The results show that multi-Terabit-per-second links are feasible at distances of up to 20 m when utilizing 1024 × 1024 UM-MIMO systems at 0.3 THz and 1 THz.

Ultra-Massive MIMO Channel Modeling for Graphene-Enabled Terahertz-Band Communications