Non-Orthogonal HARQ for UAV-Aided THz Systems: Design and Analysis

This letter addresses the error-control design for unmanned aerial vehicles (UAV)-aided Terahertz (THz) systems. Particularly, we propose the design of a non-orthogonal chase combining hybrid automatic repeat request (N-CC-HARQ) scheme, where the retransmission request is served together with the new frame through a nonorthogonal signal su-perposition within the same time slot. The performance of the proposed N-CC-HARQ is evaluated over the THz channels incorporating path loss, fading, and pointing misalignment. Different performance metrics, including frame error rate (FER), Goodput, and energy efficiency, are analytically obtained based on the Markov model. Numerical results confirm the effectiveness of the proposed N-CC-HARQ schemes over the state-of-the-art.