Beyond-line-of-sight communications with ducting layer

Near-surface wave propagation at microwave frequencies, especially 2 GHz and above, shows significant dependence on atmospheric ducts that are the layer in which rapid decrease in the refractive index occurs. The propagating signals in the atmospheric ducts are trapped between the ducting layer and the sea surface, so that the power of the propagating signals do not spread isotropically through the atmosphere. As a result, these signals have low path loss and can travel over the horizon. Since atmospheric ducts are nearly permanent in maritime and coastal environments, ducting layer communication is a promising method for b-LoS communications especially in naval communications. To this end, we overview the characteristics and the channel modeling approaches for ducting layer communications by outlining possible open research areas. In addition, we review the possible utilization of the ducting layer in network-centric operations to empower decision making for the b-LoS operations.