TTL-based efficient forwarding for the backhaul tier in nanonetworks

摘要

Electromagnetic-based Wireless Nano Sensor Networks (EM-WNSNs) working in the TeraHertz (THz) band are developing fast because of the high sensing resolution that benefits a wide range of applications. In EM-WNSNs, nano sinks that aggregate data from nano sensors to the Internet of Things (IoT) gateway collectively form a backhaul tier of EM-WNSNs. Unlike the data tier composed of densely deployed nano sensors that are closely connected, the backhaul tier consisting of less dense nano sinks is highly vulnerable to the dynamic channel states of THz band that is sensitive to the surrounding humidity change. Thus, a forwarding scheme that adapts to dynamic channel states is needed to ensure both connectivity and efficiency of data transfers over the backhaul. Current channel-aware approaches are based on complex hardware support that cannot be deployed on nano devices due to the size constraints. To solve this problem, the Time-To-Live (TTL)-based Efficient Forwarding (TEFoward) with low complexity is proposed for the backhaul tier of multi-hop polling-based EM-WNSNs. In TEFoward, the functions carried by polling beacons are diversified besides data extraction. Nano sinks select forwarders and direct packets based on the duplicate counts and TTL values of polling beacons which reflect the latest topology information. Demanding lightweight resource support, TEFoward achieves high end-to-end data delivery ratio and energy efficiency.