Alessandro Sturniolo

OptoCOMM: Development and experimentation of a new optical wireless underwater modem

This paper presents our recent advancements in the development of the underwater optical wireless modems, designed within the OptoCOMM project. The target performance of the optical modem is to achieve the data rate of 10 Mbit/s at a distance of at least 10 m in presence of sunlight. The transmitter is based on blue Light Emitting Diode (LED) technology. The modem will be developed in three versions to be integrated in Littoral Ocean Observatory Network (LOON) test-bed, and add a novel technology to the infrastructure of the FP7-SUNRISE project. We tested the first version of the modems in a typical shallow harbour water (1 m depth), in the same location of the LOON to validate the adopted technology. The seawater of the test-bed is characterized by a medium-high turbidity (about 1 FTU), which heavily affects the optical communication in terms of attenuation. All tests were run in sunny summer days with very high sunlight illumination level (~ 100 klux). Despite the challenging conditions, we achieved successful transmission at 10 Mbit/s over 7.5 m distance.

Design and characterization of the optical layer of a novel pair of underwater VLC modems

We report on the design and experimental characterization of a novel pair of underwater wireless optical modems. Each of them is equipped with a blue LED array as transmitter, an APD photodiode as receiver and a pin photodiode for optical power monitoring. The modems are designed to operate at 10 Mbit/s (10BaseT Ethernet, Manchester-coded signal) in harsh conditions, i.e. in turbid water and with strong sunlight. Successful lab experiments and final sea tests confirm the validity of our approach.

Demonstrating practical indoor LTE-over-optical wireless

We show practical feasibility of Long-Term Evolution (LTE) based indoor coverage using optical wireless communication, exploiting commercially available Light Emitting Diodes (LEDs). A common LTE-Advanced signal is distributed in downlink by a visible LED, and in uplink by infrared LED (IR-LED). We demonstrate the bidirectional transmission operating in non-directed line-of-sight configuration. Assuming a distance of 2 m (ceiling to desk), the effective coverage is around 12 m2, with no need of complex line-of-sight tracking systems. These results indicate that this scheme has great potential for practical Visible Light Communication (VLC) system implementations in small-cell indoor environments and could be helpful for overcoming the capacity needs of the future indoor cellular networks.