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| Introduced | March 2011 |
|---|---|
| Industry | Digital Communication |
| Connector type | Visible light communication |
| Physical range | visible light spectrum, ultraviolet and infrared radiation |
military). [1]
| | |
| Introduced | March 2011 |
|---|---|
| Industry | Digital Communication |
| Connector type | Visible light communication |
| Physical range | visible light spectrum, ultraviolet and infrared radiation |
military). [1]
Li-Fi is a derivative of optical wireless communications (OWC) technology, which uses light from light-emitting diodes (LEDs) as a medium to deliver network, mobile, high-speed communication in a similar manner to Wi-Fi. [2] The Li-Fi market was projected to have a compound annual growth rate of 82% from 2013 to 2018 and to be worth over $6 billion per year by 2018. [3] However, the market has not developed as such and Li-Fi remains with a niche market. [4]
Visible light communications (VLC) works by switching the current to the LEDs off and on at a very high speed, beyond the human eye's ability to notice. [5] Technologies that allow roaming between various Li-Fi cells, also known as handover, may allow to seamlessly transition between Li-Fi. The light waves cannot penetrate walls which translates to a much shorter range, and a lower hacking potential, relative to Wi-Fi. [6] [7] Direct line of sight is not always necessary for Li-Fi to transmit a signal and light reflected off walls can achieve 70 Mbit/s. [8] [9]
Li-Fi can potentially be useful in electromagnetic sensitive areas without causing electromagnetic interference. [6] [10] [7] Both Wi-Fi and Li-Fi transmit data over the electromagnetic spectrum, but whereas Wi-Fi utilizes radio waves, Li-Fi uses visible, ultraviolet, and infrared light. [11] Researchers have reached data rates of over 224 Gbit/s, [12] which was much faster than typical fast broadband in 2013. [13] [14] Li-Fi is expected to be ten times cheaper than Wi-Fi. [15] The first commercially available Li-Fi system was presented at the 2014 Mobile World Congress in Barcelona.
Although Li-Fi LEDs would have to be kept on to transmit data, they could be dimmed to below human visibility while still emitting enough light to carry data. [15] This is also a major bottleneck of the technology when based on the visible spectrum, as it is restricted to the illumination purpose and not ideally adjusted to a mobile communication purpose, given that other sources of light, for example the sun, will interfere with the signal. [16]
Since Li-Fi's short wave range is unable to penetrate walls, transmitters would need to be installed in every room of a building to ensure even Li-Fi distribution. The high installation costs associated with this requirement to achieve a level of practicality of the technology is one of the potential downsides. [3] [5] [17]
The initial research on Visible Light Communication (VLC) was published by the Fraunhofer Heinrich-Hertz-Institute in September 2009, showcasing data rates of 125 Mbit/s over a 5 m distance using a standard white LED. [18] In 2010, transmission rates were already increased to 513 Mbit/s using the DMT modulation format. [19]
During his 2011 TED Global Talk, Professor Harald Haas, a Mobile Communications expert at the University of Edinburgh, introduced the term "Li-Fi" while discussing the concept of "wireless data from every light". [20]
The general term "visible light communication" (VLC), whose history dates back to the 1880s, includes any use of the visible light portion of the electromagnetic spectrum to transmit information. The D-Light project, funded from January 2010 to January 2012 at Edinburgh's Institute for Digital Communications, was instrumental in advancing this technology, with Haas also contributing to the establishment of a company for its commercialization. [21] [22]
In October 2011, the Fraunhofer IPMS research organization and industry partners formed the Li-Fi Consortium, to promote high-speed optical wireless systems and to overcome the limited amount of radio-based wireless spectrum available by exploiting a completely different part of the electromagnetic spectrum. [23]
The practical demonstration of VLC technology using Li-Fi [24] took place in 2012, with transmission rates exceeding 1 Gbit/s achieved under laboratory conditions. [25] In 2013, laboratory tests achieved speed of up to 10 Gbit/s. By August 2013, data rates of approximately 1.6 Gbit/s were demonstrated over a single color LED. [26] A significant milestone was reached in September 2013 when it was stated that Li-Fi, or VLC systems in general, did not absolutely require line-of-sight conditions. [27] In October 2013, it was reported Chinese manufacturers were working on Li-Fi development kits. [28]
In April 2014, the Russian company Stins Coman announced the BeamCaster Li-Fi wireless local network, capable of data transfer speeds up to 1.25 gigabytes per second (GB/s). They foresee boosting speeds up to 5 GB/s in the near future. [29] In the same year, Sisoft, a Mexican company, set a new record by transferring data at speeds of up to 10 GB/s across a light spectrum emitted by LED lamps. [30]
The advantages of operating detectors such as APDs in Geiger-mode as single photon avalanche diode (SPAD) were demonstrated in May 2014, highlighting enhanced energy efficiency and receiver sensitivity . [31] This operational mode also facilitated quantum-limited sensitivity, enabling receivers to detect weak signals from considerable distances. [32]
In June 2018, Li-Fi successfully underwent testing at a BMW plant in Munich for industrial applications under the auspices of the Fraunhofer Heinrich-Hertz-Institute. [33]
In August 2018, Kyle Academy in Scotland, piloted the usage within its premises, enabling students to receive data through rapid on–off transitions of room lighting. [34]
In June 2019, Oledcomm, a French company, showcased its Li-Fi technology at the 2019 Paris Air Show. [35]
 | This section may be too technical for most readers to understand.(June 2022) |
Like Wi-Fi, Li-Fi is wireless and uses similar 802.11 protocols, but it also uses ultraviolet, infrared and visible light communication. [36]
One part of VLC is modeled after communication protocols established by the IEEE 802 workgroup. However, the IEEE 802.15.7 standard is out-of-date: it fails to consider the latest technological developments in the field of optical wireless communications, specifically with the introduction of optical orthogonal frequency-division multiplexing (O-OFDM) modulation methods which have been optimized for data rates, multiple-access, and energy efficiency. [37] The introduction of O-OFDM means that a new drive for standardization of optical wireless communications is required.[ citation needed ]
Nonetheless, the IEEE 802.15.7 standard defines the physical layer (PHY) and media access control (MAC) layer. The standard is able to deliver enough data rates to transmit audio, video, and multimedia services. It takes into account optical transmission mobility, its compatibility with artificial lighting present in infrastructures, and the interference which may be generated by ambient lighting. The MAC layer permits using the link with the other layers as with the TCP/IP protocol.[ citation needed ]
The standard defines three PHY layers with different rates:
The modulation formats recognized for PHY I and PHY II are on–off keying (OOK) and variable pulse-position modulation (VPPM). The Manchester coding used for the PHY I and PHY II layers includes the clock inside the transmitted data by representing a logic 0 with an OOK symbol "01" and a logic 1 with an OOK symbol "10", all with a DC component. The DC component avoids light extinction in case of an extended run of logic 0's.[ citation needed ]
In July 2023, the IEEE published the 802.11bb standard for light-based networking, intended to provide a vendor-neutral standard for the Li-Fi market.
Many experts foresee a movement towards Li-Fi in homes because it has the potential for faster speeds and its security benefits with how the technology works. Because the light sends the data, the network can be contained in a single physical room or building reducing the possibility of a remote network attack. Though this has more implications in enterprise and other sectors, home usage may be pushed forward with the rise of home automation that requires large volumes of data to be transferred through the local network. [39]
Most remotely operated underwater vehicles (ROVs) are controlled by wired connections. The length of their cabling places a hard limit on their operational range, and other potential factors such as the cable's weight and fragility may be restrictive. Since light can travel through water, Li-Fi based communications could offer much greater mobility. [40] [ unreliable source ] Li-Fi's utility is limited by the distance light can penetrate water. Significant amounts of light do not penetrate further than 200 meters. Past 1000 meters, no light penetrates. [41]
Efficient communication of data is possible in airborne environments such as a commercial passenger aircraft utilizing Li-Fi. Using this light-based data transmission will not interfere with equipment on the aircraft that relies on radio waves such as its radar lifi connectivity. [42]
Increasingly, medical facilities are using remote examinations and even procedures. Li-Fi systems could offer a better system to transmit low latency, high volume data across networks.[ citation needed ] Besides providing a higher speed, light waves also have reduced effects on medical instruments. An example of this would be the possibility of wireless devices being used in MRIs similar radio sensitive procedures. [42] Another application of LiFi in hospitals is localisation of assets and personnel. [43]
Vehicles could communicate with one another via front and back lights to increase road safety. Street lights and traffic signals could also provide information about current road situations. [44]
Due to the specific properties of light, the optical beams can be bundled especially well in comparison to radio-based devices, allowing highly directional Li-Fi systems to be implemented. Devices have been developed for outdoor use that make it more difficult to access the data due to their low beam angle, thus increasing the security of the transmission. These can be used, for example, for building-to-building communication or for networking small radio cells.
Anywhere in industrial areas data has to be transmitted, Li-Fi is capable of replacing slip rings, sliding contacts, and short cables, such as Industrial Ethernet. Due to the real-time of Li-Fi (which is often required for automation processes), it is also an alternative to common industrial Wireless LAN standards. Fraunhofer IPMS, a research organization in Germany states that they have developed a component which is very appropriate for industrial applications with time-sensitive data transmission. [45]
Street lamps can be used to display advertisements for nearby businesses or attractions on cellular devices as an individual passes through. A customer walking into a store and passing through the store's front lights can show current sales and promotions on the customer's cellular device. [46]
In warehousing, indoor positioning and navigation is a crucial element. 3D positioning helps robots to get a more detailed and realistic visual experience. Visible light from LED bulbs is used to send messages to the robots and other receivers and hence can be used to calculate the positioning of the objects. [47]
IEEE 802.15 is a working group of the Institute of Electrical and Electronics Engineers (IEEE) IEEE 802 standards committee which specifies Wireless Specialty Networks (WSN) standards. The working group was formerly known as Working Group for Wireless Personal Area Networks.
IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) technical standards, and specifies the set of medium access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) computer communication. The standard and amendments provide the basis for wireless network products using the Wi-Fi brand and are the world's most widely used wireless computer networking standards. IEEE 802.11 is used in most home and office networks to allow laptops, printers, smartphones, and other devices to communicate with each other and access the Internet without connecting wires. IEEE 802.11 is also a basis for vehicle-based communication networks with IEEE 802.11p.
Free-space optical communication (FSO) is an optical communication technology that uses light propagating in free space to wirelessly transmit data for telecommunications or computer networking. "Free space" means air, outer space, vacuum, or something similar. This contrasts with using solids such as optical fiber cable.
The Infrared Data Association (IrDA) is an industry-driven interest group that was founded in 1994 by around 50 companies. IrDA provides specifications for a complete set of protocols for wireless infrared communications, and the name "IrDA" also refers to that set of protocols. The main reason for using the IrDA protocols had been wireless data transfer over the "last one meter" using point-and-shoot principles. Thus, it has been implemented in portable devices such as mobile telephones, laptops, cameras, printers, and medical devices. The main characteristics of this kind of wireless optical communication are physically secure data transfer, line-of-sight (LOS) and very low bit error rate (BER) that makes it very efficient.
In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer: the layer most closely associated with the physical connection between devices. The physical layer provides an electrical, mechanical, and procedural interface to the transmission medium. The shapes and properties of the electrical connectors, the frequencies to transmit on, the line code to use and similar low-level parameters, are specified by the physical layer.
Wireless communication is the transfer of information (telecommunication) between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most common wireless technologies use radio waves. With radio waves, intended distances can be short, such as a few meters for Bluetooth, or as far as millions of kilometers for deep-space radio communications. It encompasses various types of fixed, mobile, and portable applications, including two-way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other examples of applications of radio wireless technology include GPS units, garage door openers, wireless computer mouse, keyboards and headsets, headphones, radio receivers, satellite television, broadcast television and cordless telephones. Somewhat less common methods of achieving wireless communications involve other electromagnetic phenomena, such as light and magnetic or electric fields, or the use of sound.
4G is the fourth generation of broadband cellular network technology, succeeding 3G and preceding 5G. A 4G system must provide capabilities defined by the International Telecommunication Union (ITU) in IMT Advanced. Potential and current applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, and 3D television.
In telecommunications, visible light communication (VLC) is the use of visible light as a transmission medium. VLC is a subset of optical wireless communications technologies.
Fiber to the x or fiber in the loop is a generic term for any broadband network architecture using optical fiber to provide all or part of the local loop used for last mile telecommunications. As fiber optic cables are able to carry much more data than copper cables, especially over long distances, copper telephone networks built in the 20th century are being replaced by fiber.
A home network or home area network (HAN) is a type of computer network that facilitates communication among devices within the close vicinity of a home. Devices capable of participating in this network, for example, smart devices such as network printers and handheld mobile computers, often gain enhanced emergent capabilities through their ability to interact. These additional capabilities can be used to increase the quality of life inside the home in a variety of ways, such as automation of repetitive tasks, increased personal productivity, enhanced home security, and easier access to entertainment.
The physical-layer specifications of the Ethernet family of computer network standards are published by the Institute of Electrical and Electronics Engineers (IEEE), which defines the electrical or optical properties and the transfer speed of the physical connection between a device and the network or between network devices. It is complemented by the MAC layer and the logical link layer. An implementation of a specific physical layer is commonly referred to as PHY.
Ethernet in the first mile (EFM) refers to using one of the Ethernet family of computer network technologies between a telecommunications company and a customer's premises. From the customer's point of view, it is their first mile, although from the access network's point of view it is known as the last mile.
LVX System of Companies is the inventor of Visible Light Communication and Light Fidelity market. The LVX system is a collection of LED light bulbs and specialized equipment which allow the transmission of data through light photons- pulse width modulation (PWM) of the LED.
IEEE 802.11b-1999 or 802.11b is an amendment to the IEEE 802.11 wireless networking specification that extends throughout up to 11 Mbit/s using the same 2.4 GHz band. A related amendment was incorporated into the IEEE 802.11-2007 standard.
IEEE 802.11g-2003 or 802.11g is an amendment to the IEEE 802.11 specification that operates in the 2.4 GHz microwave band. The standard has extended link rate to up to 54 Mbit/s using the same 20 MHz bandwidth as 802.11b uses to achieve 11 Mbit/s. This specification, under the marketing name of Wi‑Fi, has been implemented all over the world. The 802.11g protocol is now Clause 19 of the published IEEE 802.11-2007 standard, and Clause 19 of the published IEEE 802.11-2012 standard.
Gigabit Home Networking (G.hn) is a specification for wired home networking that supports speeds up to 2 Gbit/s and operates over four types of legacy wires: telephone wiring, coaxial cables, power lines and plastic optical fiber. Some benefits of a multi-wire standard are lower equipment development costs and lower deployment costs for service providers.
IEEE 802.11ac-2013 or 802.11ac is a wireless networking standard in the IEEE 802.11 set of protocols, providing high-throughput wireless local area networks (WLANs) on the 5 GHz band. The standard has been retroactively labelled as Wi-Fi 5 by Wi-Fi Alliance.
IEEE 802.11ah is a wireless networking protocol published in 2017 called Wi-Fi HaLow as an amendment of the IEEE 802.11-2007 wireless networking standard. It uses 900 MHz license-exempt bands to provide extended-range Wi-Fi networks, compared to conventional Wi-Fi networks operating in the 2.4 GHz, 5 GHz and 6 GHz bands. It also benefits from lower energy consumption, allowing the creation of large groups of stations or sensors that cooperate to share signals, supporting the concept of the Internet of things (IoT). The protocol's low power consumption competes with Bluetooth, LoRa, and Zigbee, and has the added benefit of higher data rates and wider coverage range.
Optical wireless communications (OWC) is a form of optical communication in which unguided visible, infrared (IR), or ultraviolet (UV) light is used to carry a signal. It is generally used in short-range communication.
IEEE802.11bb is a line-of-sight light-based wireless networking standard that is part of the 802.11 suite of standards, which defines an interoperable communications protocol for Li-Fi devices. Its proponents state that it will allow for very high speed communication that is faster than Wi-Fi.
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