A Load-Aware Dynamic TDMA Protocol for Terahertz Wireless NanoSensor Networks

Wireless NanoSensor Networks (WNSNs) is a new type of networks which combines nanotechnology and sensor networks, having promising applications in the biomedical, industrial, environmental and military fields. Due to the peculiarities of WNSNs, such as molecular absorption noise in the Terahertz channel and the limited capacities of nano-nodes, novel Medium Access Control (MAC) protocols are needed to regulate access to the channel and coordinate transmission orders among nano-nodes. In this paper, a load-aware dynamic TDMA (LAD-TDMA) protocol is proposed. This protocol is built on a novel pulsed-based communication scheme called TS-OOK and avoids symbol collisions to achieve high energy efficiency. LAD-TDMA adopts a dynamic TDMA-based time slot allocation mechanism according to the current number and corresponding traffic of source nodes, the transmission peculiarities of Terahertz channel. The performance of the protocol is evaluated and analyzed in terms of energy consumption, average end-to-end delay and average throughput, by using the NS3 simulation platform. Results show that LAD-TDMA is energy efficient and advantageous in average end-to-end delay and average throughput, which is proved to be suitable to support node-intensive and load-unbalanced WNSNs, by considering the properties of Terahertz band, energy limitation of nano-devices and nano-nodes' traffic.