  In this paper, a novel hierarchical beamtracking approach, which is suitable
for terahertz (THz) wireless systems, is presented. The main idea is to employ
a prediction based algorithm with a multi-resolution codebook, in order to
decrease the required overhead of tracking and increase its robustness. The
efficiency of the algorithm is evaluated in terms of the average number of
pilots and mean square error (MSE) and is compared with the corresponding
performance of the fast channel tracking (FCT) algorithm. Our results highlight
the superiority of the proposed approach in comparison with FCT, in terms of
tracking efficiency with low overhead.
