Visible Light Communications (VLC), also known in general terms as Light Fidelity (LiFi), is an optical communication technology that complements, or in some applications replaces, current radio frequency wireless networks such as WI-FI or Bluetooth, among others. The main difference between both lies mainly in the wavelength of the electromagnetic radiation used to transmit the data, which in the case of LiFi is in the range of optical signals, both in the visible and infrared spectrum. In this way, for example, by simply installing an electrical to an optical converter to any LED bulb, we can make it capable not only of emitting light but also of transmitting data (a concept that has come to be known as "illumination").
In the current situation in many countries, in a state of alarm and confinement due to the "COVID-19" pandemic, all wireless technologies have become very interesting due to the need for social isolation among people. An example of this is the payments with credit cards in point of sale terminals (POS), where the user has to enter manually the PIN of the card with the consequent need of cleaning the terminal after each payment; or even the keys of our houses, where we are told from the media the importance of cleaning them. Therefore, in these situations, we need technologies that facilitate the task of isolating the user interfaces by using the terminals of each individual.
Visible Light Communication (VLC) has been presented as a promising technology for indoor and outdoor mobile networks, providing high bandwidth and unregulated spectrum usage, among other interesting capabilities. Visible LEDs (white LEDs or RGB LEDs) are included not only in new solid-state lighting systems (LED lamps) but also in many COST devices, such as smartphones or laptops. These lighting devices and their ubiquity are the reason for the development of VLC, since they are capable of transmitting data at speeds high enough to support the services and transmission rates (low, medium and high) demanded by different applications.
VLC is defined by the European Commission as one of the six key enabling technologies for the future. Recent demand factors as a result of the burgeoning mobile phone industry and the rapid evolution of LED-based lighting are also driving this interest. VLC is a disruptive technology in its application in the field of secure data transmissions and is also closely linked to environmental protection and, above all, to human health (by reducing the use of radio signals).
The sector to which VLC-related applications are directed is a growing market that was valued in 2015 at around 455 million US dollars, according to data from the Grand View Research, Inc. a U.S. market research and consulting firm.
Nowadays, the mobile phone is an almost essential communication tool in our lives and it has been a long time since it was only used to communicate with mobility, to integrate an endless number of applications and utilities that make our daily life more comfortable. With LightBee's Lightkey application (https://lightbee.es), we intend to offer a solution that allows the user to unify access control or secure payments on the mobile phone. To do this, we use the LED devices available on mobile phones, such as the camera flash (a high-intensity white LED) or the screen itself. These light emitters can be controlled by the device's software and can be used to transmit information (VLC) over a short distance. They also have control over the optical intensity, so it is possible to adapt the range of the emitted signal depending on the distance. The main advantage is that all the necessary hardware for this process is already included in the mobile device and is accessible by programming. Similarly, services are also available that allow the signal to be encoded for secure transmission, as well as security procedures to prevent fraudulent use of the device in the event of theft.
The communication technique to be used is within the VLC paradigms performing the transmission of an optical code in the visible spectrum, which is transmitted at a very high speed, sufficient to avoid the possibility of being detected by a video camera or by the human eye (a simple flash of light would be seen, the individual transmission values not being distinguishable). Furthermore, the signal cannot be copied from an external device, because, due to its directivity and randomness, there is no radiated signal susceptible of being captured from an external system. Unlike other technologies, such as BLUETOOTH or NFC (Near Field Communications) VLC systems do not have the problems associated with the difficult management of the area covered by the communication. Thus, a BLUETOOTH transmission can be detected in an area of more than 300 m2 in the transaction environment, compromising the security of the system. At the other extreme, NFC-based techniques require very close positioning, and even direct contact, between the devices for their operation. This does not prevent them from still being susceptible to detection or interference. In fact, many of the latest generations of smartphones do not incorporate these systems due to their cost and electromagnetic compatibility problems. Another important point is that VLC systems are robust against electromagnetic interference, such as that generated by radiofrequency communications inhibitors, typical in security systems or those produced in industrial environments, which make communications impossible or false.
In Lightkey locks, it is not necessary to give a key or access card, avoiding displacements and decreasing the direct contact. We add, therefore, security in the spread of pandemics like COVID-19. Our system is easily implemented in a home allowing easy access to it in emergency circumstances. Our system is easily implemented in a home, allowing easy access to it in emergency circumstances. It is an economical, low energy consumption system that takes advantage of the existing infrastructure. It offers user confidence since he sees when he acts. Totally designed for use, it is not an adaptation like BLUETOOTH, NFC, etc. and from a technology perspective, it improves the "Man in the Middle" security failure by being compatible with other systems and immune to radio frequency inhibitors. As an additional security feature, the lock used in the Lightkey systems is prepared for FIRE CONTROL and allows the opening from the inside, even if the lock has the key lock on, thus ensuring the exit in any situation and is returned to the locked state with key passers simply by moving the handle.
