Biblio

In the upcoming advent of 6G networks, underwater communications are expected to play a relevant role in the context of overlapping hybrid wireless networks, following a multilayer architecture i.e., aerial-ground-underwater. The concept of Internet of Underwater Things defines different communication and networking technologies, as well as positioning and tracking services, suitable for harsh underwater scenarios. In this paper, we present a footprinting localization algorithm based on optical wireless signals in the visible range. The proposed technique is based on a hybrid Radio Frequency (RF) and Visible Light Communication (VLC) network architecture, where a central RF sensor node holds an environment channel gain map i.e., database, that is exploited for localization estimation computation. A recursive localization algorithm allows to estimate user positions with centimeter-based accuracy, in case of different turbidity scenarios.

We propose and demonstrate an indoor optical bi-directional communication system employing near-infrared (NIR) and visible light as carriers. Such a communication technology is attractive wherein red color could be deployed for down streaming purpose via, for instance, LiFi (light fidelity) system, and NIR color for up streaming purpose. This system concept is implemented over a simultaneous bidirectional audio signal transmission and reception over 0.6m indoor wireless channel. Besides, designing the transceiver circuits from off the shelf components, frequency scrambling encryption and decryption technique is also integrated in the system for security purpose. The communication system is optically characterized in terms of line-of-sight laser misalignment and communication distance.