  Terahertz (THz) frequencies have recently garnered considerable attention due
to their potential to offer abundant spectral resources for communication, as
well as distinct advantages in sensing, positioning, and imaging. Nevertheless,
practical implementation encounters challenges stemming from the limited
distances of signal transmission, primarily due to notable propagation,
absorption, and blockage losses. To address this issue, the current strategy
involves employing ultra-massive multi-input multi-output (UMMIMO) to generate
high beamforming gains, thereby extending the transmission range. This paper
introduces an alternative solution through the utilization of cell-free massive
MIMO (CFmMIMO) architecture, wherein the closest access point is actively
chosen to reduce the distance, rather than relying solely on a substantial
number of antennas. We compare these two techniques through simulations and the
numerical results justify that CFmMIMO is superior to UMMIMO in both spectral
and energy efficiency at THz frequencies.
