On the Energy Efficiency of Relay-Assisted In- Vivo Nano- Networks Communications

We evaluate the performance in terms of energy efficiency of multiple cooperative schemes for in-vivo nano-networks in the terahertz band. More specifically, we consider a multiple relay-aided network where the relays are capable of operating under: i) all-active relaying, where multiple relay nodes are placed midway between the transmitter $(S)$ and the receiver $(D)$ nodes in order to forward the messages; ii) selective relaying, where, similarly to the all-active scheme, multiple relay nodes are placed between $S$ and $D$, but only a selected relay forward the message; iii) multi-hop relaying, where, instead of placing the relays midway between $S$ and $D$, the relays are evenly distributed in the communication path. Our analysis demonstrates that the optimal scheme is distance-dependent and, for larger distances, the multi-hop scheme outperforms the other aforementioned schemes.