Routing Protocol Design for Directional and Buffer-limited Terahertz Communication Networks

Terahertz (THz) band (0.1-10 THz) communication is envisioned as a potential key wireless technology to satisfy the need for much higher wireless data rates. THz-band communication supports a huge bandwidth. However, this advantage comes at the cost of a very high propagation loss. Thus, highly directional antennas (DAs) are simultaneously utilized in both transmission and reception to establish communication links beyond several meters. The application of highly DAs introduces many challenges for multi-hop routing. Among others, the best routing path dynamically changes since the directional communication links are periodically on and off, as determined by the DAs' current directions. Another challenge for routing protocol design comes from the limited memory or buffer size of THz devices, which is filled quickly when concurrent Terabit-per-second (Tbps) transmissions are handled. The buffer will be easily blocked by a locally stored packet that keeps waiting for the availability of the “best” route. This issue becomes even worse in directional networks, where such route may not be available shortly, and severely affects the network performance. In this paper, an adaptive routing protocol for highly dynamic buffer-limited directional THz communication networks is developed. A simulation framework is developed to study the iterations and updates between network performance and the choice made by each node. Extensive simulation results are provided to demonstrate the improvements of our proposed routing protocol.