Browsing by Issue Date, starting with "2022-03-06"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- VLC-based geo-localization for automated logistics control using AVGsPublication . Louro, Paula; Rodrigues, João; Vieira, Manuela; Vieira, Manuel Augusto; Vieira, PedroIncreasing interest in indoor navigation has recently been generated by devices with wireless communication capabilities that enabled a wide range of applications and services. The rise of the Internet of Things (IoT) and the inherent end-to end connectivity of billions of devices is very attractive for indoor localization and proximity detection. Other fields, such as, marketing and customer assistance, health services, asset management and tracking, can also benefit from indoor localization. Different techniques and wireless technologies have been proposed for indoor location, as the traditional Global Positioning System (GPS) has a very poor, unreliable performance in a closed space. The work presented in this research proposes the use of an indoor localization system based on Visible Light Communication (VLC) to support the navigation and operational tasks of Autonomous Guided Vehicles (AVG) in an automated warehouse. The research is mainly focused on the development of the navigation VLC system, transmission of control data information and decoding techniques. As part of the communication system, trichromatic white LEDs are used as emitters and a-SiC:H/a-Si:H based photodiodes with selective spectral sensitivity, are used as receivers. Through the modulation of the RGB LEDs, the downlink channel establishes an infrastructure-to-vehicle link (I2V) and provides position information to the vehicle. The decoding strategy is based on accurate calibration of the output signal. Characterization of the transmitters and receivers, description of the coding schemes and decoding algorithms will be the focus of discussion in this paper.
- Management of split intersections using vehicular visible light communicationPublication . Vieira, Manuel Augusto; Vieira, Manuela; Louro, Paula; Vieira, PedroVehicle Communication Systems consist of vehicles and roadside units that communicate with one another in order to exchange information, such as traffic information and safety warnings. Split intersections are an innovative solution for congested urban areas. In this case, a congested two-way-two-way intersection is made into two lighter intersections. It facilitates a smoother flow with less driver delay, by reducing the number of conflict points and improving the travel time. Based on Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I) and Infrastructure-to-Vehicle (I2V) communications, we propose a Visible Light Communication system that can safely manage vehicles crossing an intersection using Edge of Things facilities. The connected vehicles communicate with each other and with the infrastructure through visible light, by using headlights, street lamps, and traffic signals, In parallel, an intersection manager coordinates the traffic flow and interacts with the vehicles through internally installed Driver Agents. Request/response mechanisms and time/space relative pose concepts are used to control the flow of vehicles safely crossing the intersection. A communication scenario is established, and a “mesh/cellular” hybrid network configuration is proposed. Data is encoded, modulated and converted into light signals emitted by the transmitters. As receivers and decoders, optical sensors with light filtering properties, are used. Bidirectional communication between the infrastructure and the vehicles is tested, using the VLC request/response concept. Results show that the short-range mesh network ensures a secure communication from street lamp controllers to the edge computer through the neighbor traffic light controller with active cellular connection and enables peer-to-peer communication, to exchange information between V-VLC ready connected cars.
- Cooperative self-localization and wayfinding services through visible light communicationPublication . Vieira, Manuela; Vieira, Manuel Augusto; Louro, Paula; Fantoni, Alessandro; Vieira, PedroA Visible Light Communication (VLC) cooperative system that supports guidance services and uses an edge/fog based architecture for wayfinding services is presented. The integrated dynamic navigation system consists of multiple transmitters (luminaries) which transmit the map information and path messages necessary for wayfinding. The luminaires used for downlink transmission are equipped with one of two types of controllers: mesh controllers or cellular controllers, which, respectively, forward messages to other devices in the vicinity or to the central manager. Mobile optical receivers, collect the data, extracts theirs location to perform positioning and, concomitantly, the transmitted data from each transmitter. Uplink transmission is implemented and the best route to navigate through venue calculated. Each luminaire, through VLC, reports its geographic position and specific information to the users, making it available for use. Bidirectional communication is implemented and the best route to navigate through venue calculated. Buddy wayfinding services are also considered. Results indicate that the system is able to perform not just the self-localization, but also infer the travel direction and interact with it, optimizing the route to a static or dynamic destination.
- Navigation, routing and geolocation through visible light communicationPublication . Vieira, Manuela; Vieira, Manuel Augusto; Louro, Paula; Fantoni, Alessandro; Vieira, PedroTo support people’s wayfinding activities in crowded buildings this paper proposes a method able to generate landmark route and alert instructions using Visible Light Communication .The system is composed of several ceiling luminaries transmitters which send the map information, alerts and the path messages required to wayfinding. The system informs the users, in real time, not only of the best route to the desired destination, through a route without clusters of users, but also of crowded places. Data is encoded, modulated and converted into light signals. An architecture based on a mesh cellular hybrid structure was used. The luminaires are equipped with one of two types of nodes: a “mesh” controller that connects with other nodes in its vicinity and can forward messages to other devices in the mesh, acting like routers nodes in the network and a “mesh/cellular” hybrid controller, that is also equipped with a modem providing IP base connectivity to the central manager services. Each luminaire for downlink can forward messages to other devices or to the central manager services. Mobile optical receivers, collect the data, extracts theirs location to perform positioning and, concomitantly, the transmitted data from each transmitter. Uplink transmission is implemented and the best route to navigate through venue calculated. Buddy wayfinding services are also considered. The results show that the system makes possible not only the self-localization, but also to infer the travel direction and to interact with information received optimizing the route towards a static or dynamic destination.