Expedited Neighbor Discovery in Directional Terahertz Communication Networks Enhanced by Antenna Side-Lobe Information

Terahertz (THz)-band (0.1-10 THz) communication is envisioned as a key wireless technology of the next decade, able to support wireless Terabit-per-second links in 6G systems. THz communication exhibits an extremely large bandwidth (tens to hundreds of GHz) at the cost of a very high path loss (>100 dB for distances beyond a few meters). Therefore, highly directional antennas (DAs) are needed simultaneously in transmission and reception at all times to establish reliable communication links. The application of highly DAs introduces new challenges in the neighbor discovery process. In this paper, a time-efficient neighbor discovery protocol for THz-band communication networks is proposed. The protocol expedites the neighbor discovery process by leveraging the full antenna radiation pattern to detect a series of effective signals and map them to the universal signal patterns, which indicate the potential direction of the signal source. A mathematical framework is developed to compare the neighbor discovery protocols with and without the antenna side-lobes information in free space. The X60 testbed is utilized to validate the proposed neighbor discovery protocol. Furthermore, a feasibility analysis of the proposed protocol inside a bounded space (e.g., a square room) is conducted. Numerical results are presented to illustrate the performance improvements achieved by the proposed protocol when compared to the traditional neighbor discovery protocols with only main-lobe information.