Frequency Selection Strategies Under Varying Moisture Levels in Wireless Nano-Networks

Graphene-based nano-antennas can enable wireless communications between nano-scale devices. Large numbers of nano-devices can be connected to form networks enabling a variety of applications, such as agricultural crop monitoring. Graphennas will resonate in the THz band, so high data rates are theoretically achievable. However, properties of THz communications, notably the sensitivity to moisture levels in the communication path, strongly affect the achievable data rates, so frequency selection becomes a challenge. This paper considers a crop monitoring nano-networking application in which moisture levels can vary significantly in line with crop monitoring schedules. A number of frequency selection strategies for clusters of nano-devices that adapt to prevailing moisture levels are proposed. These strategies aim to optimize the overall transmission capacity of a nanonetwork based on the limitations of the channel condition. Results of a simulation study show that the different selection strategies provide different levels of trade-off between efficient use of the available spectrum, total power consumption of the nano-devices, and the total transmission capacity.