Robust Beamforming Under Beam Split and Angular Uncertainty in Terahertz Communications

초록

In this letter, we propose a novel expected sum rate maximization algorithm called robust beam split and angular uncertainty (RoBA) for a terahertz (THz) hybrid precoding downlink system. To mitigate the effects of beam split and angular uncertainty that occur in a practical wideband THz system, we introduce an array covariance matrix at each subcarrier. This matrix captures the impact of frequency-dependent array responses and statistical angular errors, enabling tractable optimization of the expected sum rate. The resulting constant modulus analog precoder design problem is solved using the Riemannian conjugate gradient (RCG) algorithm. Simulation results show that the proposed RoBA algorithm significantly improves the expected sum rate compared to existing benchmarks.

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