Cross-Layer Design for Dynamic Routing and MAC Protocols in Terahertz Nanonetworks

The advancement of nanotechnology has enabled the deployment of medical nanonetworks within the human body, further accelerated by progress in terahertz communication technologies and nanonetwork routing protocols. However, nanonodes may move in dynamic environments due to environmental influences or self-propulsion mechanisms, posing significant challenges to routing protocol design. To address this, we propose a dynamic routing protocol for nanonetworks that integrates real-time velocity vectors to account for time-varying node positions. During relay node selection, key factors such as candidate nodes' velocity vectors are comprehensively evaluated to determine the optimal relay for next-hop transmission. To ensure efficient data exchange among multiple nodes, we design a time-division multiple access (TDMA)-based media access control (MAC) protocol to prevent packet collisions and losses. The protocol assigns distinct transmission and reception time slots to different node types and implements a countdown mechanism to manage channel access and eliminate conflicts. Numerical and simulation results demonstrate that the proposed protocol significantly outperforms benchmark protocols, achieving notable improvements in both time and energy efficiency.