Visible Light communication (VLC) is an emerging technology in which data are transmitted by using ordinary LEDs as those available on lighting infrastructure or screen displays. In lighting systems the broad adoption of LEDs creates the opportunity of having a network of Internet connected LEDs, from which an end user with, for instance, a smartphone can receive location-aware information from the lighting infrastructure.
Starting from a previous project on VLC, here we investigate VLC modulation techniques compatible with a broad range of cameras, which can differ for the image acquisition method and the frame per second rate used, improving the achievable data rate without compromise the coexistence with the lighting infrastructure. The issue of wide compatibility with existing hardware is of fundamental importance as said by the IEEE task group on optical wireless communication dealing with revision of VLC standard.
Furthermore we want to create a network of transmitting LEDs connected to the Internet through a low power wide area network (LPWAN) protocol (as LoRaWAN), in order to have smart lighting and control the VLC transmitter parameters. The studies on VLC integration with the core network are important to be addressed, because in the VLC literature most works deal with point-to-point systems, and there is a lack on networking aspects that are fundamental in order to have a full communication system.
This objectives are reached using the output of a previous project, where a test-bed for point-to-point VLC communication has been established, enhancing it with low cost hardware, creating a LPWAN using the LoRaWAN network recently deployed in Rome, in order to have a complete framework of VLC communication where LEDs are remotely controlled.
The VLC modulation techniques investigated in this project have the objective to solve the synchronization and illumination issues associated with the use of massive MIMO systems in image sensor based VLC systems. In the literature, these issues have not been addressed yet, thus this project tries to paving the way for achieving a higher data rate (that is now limited to few kbit/second in OCC systems) enabled through the transmission with a very high number of LEDs by a single VLC transmitter. This achievement can, for instance, reduce the time required for an end-user with a smartphone to access the information embedded within a LED-based signage.
Moreover, we want to create a network of Internet connected LEDs with VLC capabilities, as an application in the IoT world. We want to implement the first VLC wide area network with constraints on energy consumption, and deployment cost using the LoRaWAN technology. Since the low power area networks in general and LoRa technology in particular are rather new, there is a lack of studies in the literature on LoRaWAN performances.
The network creation is feasible, and can be implemented with existing hardware present in the market and with a budget that can be affordable by this project.
As an enhancement of the testbed created with the project "ELVICOS" the project outputs are:
M1: Hardware, implementation of a Massive MIMO LEDs transmitter for high data rate VLC point-to-point link (month 1);
M2: Software, LEDs array modulation (C) (month 2);
M3: Hardware, integration of VLC Transmitters with LoRa wireless module (month 3);
M4: Software, LoRaWAN network creation (month 4).
Leading to a research test-bed where VLC multiple access techniques can be experimentally studied.
As research output are expected:
M4: Conference Paper (month 5);
M5: Journal Paper (month 8).