  Next-generation networks need to meet ubiquitous and high data-rate demand.
Therefore, this paper considers the throughput and trajectory optimization of
terahertz (THz)-enabled unmanned aerial vehicles (UAVs) in the sixth-generation
(6G) communication networks. In the considered scenario, multiple UAVs must
provide on-demand terabits per second (TB/s) services to an urban area along
with existing terrestrial networks. However, THz-empowered UAVs pose some new
constraints, e.g., dynamic THz-channel conditions for ground users (GUs)
association and UAV trajectory optimization to fulfill GU's throughput demands.
Thus, a framework is proposed to address these challenges, where a joint
UAVs-GUs association, transmit power, and the trajectory optimization problem
is studied. The formulated problem is mixed-integer non-linear programming
(MINLP), which is NP-hard to solve. Consequently, an iterative algorithm is
proposed to solve three sub-problems iteratively, i.e., UAVs-GUs association,
transmit power, and trajectory optimization. Simulation results demonstrate
that the proposed algorithm increased the throughput by up to 10%, 68.9%, and
69.1% respectively compared to baseline algorithms.
