When desktop computers were entering the workplace in large numbers, the data transfer between units was normally by cable, often ethernet with a server acting as a hub, or by “sneaker-net”—where someone carried a floppy disk of data between workstations by hand. Fiberoptics entered the picture in the 1980s as an alternative to electrical signals on ethernet or coax cable but the need for repeaters along the line was a drawback.
Then came Wi-Fi—wireless fidelity. Wi-Fi eliminated the need for physical connections to servers to gain access to local networks and the internet. Because connections established through Wi-Fi are wireless, users are given access from virtually anywhere within range. And because radio waves can penetrate through walls, users can enjoy Wi-Fi connections within a 20 to 50-meter radius from the source.
The radio spectrum is part of the electromagnetic spectrum that have frequencies from 3 Hz to 3,000 GHz. Ubiquitous today, Wi-Fi is rapidly reaching a saturation point as the allotted frequencies are running out and the ease of hacking into a radio network is becoming evident. To ease the overload and provide more security, new ways to network computers is being developed.
When a RF (radio frequency) current is supplied to an antenna, an electromagnetic field is created, which propagates through any space. This creates a point where users can connect and gain access. However, Wi-Fi connections tend to be unsecure. This comes from its wide signal range that allows devices to access the network as long as they are within range. Even if the connection is password protected, all private data are vulnerable.
Early in Wi-Fi deployment, the wide range of the signals led to “wardriving,” a situation where a hacker would drive slowly in a neighborhood, using a signal seeker (sniffer) and GPS to record where Wi-Fi signals were present. That information could be used to hack into a vulnerable network and was often sold to other hackers. To counter this, companies and individuals may employ sophisticated techniques using high-end technologies to protect their data.
With the radio frequency spectrum closing rapidly on saturation, other media are being explored for wireless networking. One showing promise is Li-Fi—Light Fidelity. LiFi makes use of visible and invisible light, allowing it to have access to a greater range of available frequencies as the visible light spectrum is 10,000 times larger than the entire radio spectrum. The visible light spectrum covers frequencies from 430,000 to 770,000 GHz and colors from near ultraviolet to near infrared.
LiFi makes use of VLC (visible light communication) technology and solid-state lighting, such as LED bulbs. The light given off by the source (the transmitter) is modulated and received by a photodiode (the receiver). The signals received from the transmitter are then translated into usable data forms.
However, since LiFi uses light, which cannot penetrate walls or other solid objects, it has a significant limitation: connections are typically confined within the space where they are provided due to the nature of visible light. In establishments, lights must be tactically placed in rooms, and halls to expand the scope of the LiFi network. In open spaces, Wi-Fi’s coverage can go up to 50 meters, but LiFi can only go up to 10 meters.
Although the distance limitation is a drawback, it is also a benefit as the signals generated by LiFi are more secure from outside access. Where wardriving could find Wi-Fi networks, LiFi is invisible outside the walls of the building. Another benefit of LiFi is cost. Since it makes use of high-efficiency LED bulbs, users can enjoy lower costs in terms of energy consumption. And they only require working LED lights, which are already available within most households and other facilities, allowing for additional savings in terms of installation costs. Because there are already 14 billion light bulbs all over the world, its availability is never in question; there can be as many LiFi networks available as there are light bulbs.
One other aspect of LiFi that has limited its use is the lack of infrastructure. LiFi is actually not a new technology—the rudiments were outlined in 2011 by Harald Haas, a German Professor of Mobile Communications at the University of Edinburgh. Haas subsequently formed a company, pureLiFi, to develop the technology.
While RF signals are subject to electromagnetic interference, light isn’t. However, since LiFi works from a light bulb, the simple fact is, if all power to a light is turned off then there is no LiFi. Since there are so many frequencies of light above and below the visual spectrum, there are ways to have the lights on and the room dark.
LiFi technology can be dimmed low enough that a room will appear dark and still transmit data. There is consistent performance between 10 and 90% illumination. Currently, pureLiFi’s technology provides communication at light levels down to 60 lux. For comparison the common standard for minimum light level for reading is 400 lux. There are also other options for using invisible parts of the light spectrum such as infra-red, which is currently already being used for sending information back to the lightbulb.
LiFi is a way for data to be moved in a confined area, in some ways better than using Wi-Fi. One commonality is that both must connect to a wired access point to reach the internet. This is called the backhaul and, according to pureLiFi, there are two approaches for providing backhaul for LiFi wireless communications.
Currently, PoE (power over Ethernet) is the optimal solution for driving the network backhaul and therefore the preferred option for new installations. Or PLC (power line communications) is the preferred option for retrofit installations. PLC can be used for sharing the available capacity between lamps attached to any given system.
The long-term backhaul is resolved by using Power over Ethernet in new offices, which is proving more efficient for smart buildings and lighting. An example is the Edge Building in Amsterdam that is the current headquarters of Deloitte. The building has more than 6,000 PoE connected lighting fixtures, which resulted in a 50% reduction in installation time as well as a 25% installation cost saving.
Another application is with the United States Army in Europe where pureLiFi will supply Kitefin, a next generation optical wireless communication system using LiFi. The deal is the world’s first large scale deployment of LiFi and consists of thousands of certified offices and field-deployable LiFi units in real tactical and strategic environments. An initial pilot took place in 2019, convincing key Army stakeholders that LiFi would play a key role in the future of defense communications.
Whether Wi-Fi or LiFi, compatibility with existing backhaul and other wireless and wired systems is critical. Standards have been in place for wired networking in offices and homes since 1980 (IEEE 802) and for Wi-Fi starting in 1991 (IEEE 802.11). A Light Communications study group in IEEE is working on a protocol for LiFi tentatively labeled 802.11bb.
Meanwhile, a United Nations standardization body has defined G.hn as a family of international standards. The G.hn protocol is intended to operate over any physical networking medium in the home, such as coaxial cable, telephone wires, CAT5 cables (Ethernet), powerline, and fiberoptics leaving a single technology interconnecting any device in the home over any wire. G.hn systems can pass data at very high speeds, up to at least 1 gigabit per second and provide an in-home network that is secure from tampering or content theft while able to deliver any content anywhere throughout the home.
The HomeGrid Forum, an industry alliance of technology innovators, silicon vendors, system manufacturers, and service providers is focused on promoting and deploying G.hn for LiFi applications. For LiFi to reach its full connectivity potential for sensitive sectors such as financial services, healthcare, and robotics, it will require a robust, reliable, and proven physical layer encoding technology and a strong, solid backbone that connects the LEDs. HomeGrid feels G.hn technology is perfect for these needs.
A member of the HomeGrid Forum, Signify, developed Trulifi by Signify which can be retrofitted into existing luminaires to provide a future-proof network as well as be part of a new infrastructure. With a presence in more than 70 countries, Signify is a world leader in LED lighting innovation and is the frontrunner in the industry’s expansion of lighting systems in both the professional and consumer markets. Signify’s expertise will be instrumental as the Forum continues to innovate G.hn technology for LiFi use in airports, banks, factories, government, and defense organizations—all of which require simultaneous high security and low latency connectivity.
Trulifi is embedding MaxLinear’s G.hn chipsets to modulate the light waves to transmit data and to provide backhaul over existing wires. By leveraging their lighting infrastructure, Signify customers get the best of both worlds: a great lighting experience and a high speed wireless G.hn-encoded LiFi connection with a reliable G.hn wired backbone.
Like any technology, LiFi is suffering early “teething” problems. As more companies see advantage in joining the current proponents, LiFi should move from fad to trend and eventually to standard. Meanwhile, architects, engineers, contractors, and builders need to learn about this networking system to have their new construction ready and adaptable.
Original Article: https://constructech.com/networking-at-the-speed-of-light/
