The Li-Fi is a wireless communication system in which light is used as a carrier signal instead of traditional radio frequency as in Wi-Fi. Li-Fi is a technology that utilizes a light emitting diode to transmit data wirelessly. LiFi works by switching LEDs on and off within nanoseconds to communicate data, which is too quick to be noticed by the human eye. At the receiving end Li-Fi uses a photodetector to receive signals and convert them into streamable content.
The visible light spectrum is 10,000 times larger than the entire radio frequency spectrum hence can provide large data rates. Researchers have reached data rates of over 10 Gbit/s, which is more than 250 times faster than superfast broadband. Li-Fi is expected to be ten times cheaper than Wi-Fi. The LED lights require so little energy; they can be powered by a standard ethernet cord. Inventor Harald Haas has also suggested that the smart lights could be powered by solar cells charging batteries.
Wireless Fidelity (Wi-Fi) is the current method of sending digital/analog data over a communication medium and has become a preferred method of data transmission. At times, Wi-Fi can be very reliable but the Electromagnetic Interference (EMI) it can cause and security vulnerabilities it can create present a problem for the Navy. US Navy now wants to increase reliability of systems onboard undersea platforms through development of a VLC system.
Compared to its competing technology Wi-Fi, Li-Fi provides an increase in bandwidth (BW), elimination of EMI, and increased security. This form of connection is highly reliant on line-of-sight (LoS), as the connection can be disconnected from obstructing the light’s path. This might seem to be a negative attribute but can lead to improved security; it would eliminate data leakage.
Li-Fi can be installed, the communication in natural disaster times such as earthquakes, cyclones, tsunami or hurricanes. Li-Fi bulbs could be fixed in the streets to provide light and economical high speed internet access in each corner of the street. Li-Fi provides a safe substitute to electromagnetic interference from radio frequency communications in Hazardous environments like as mines and petrochemical plants.
In future LiFi would make possible the extensive deployment of visible light communication for a wide range of short and medium-range communication applications including wireless, local, personal, and body area networks (WLAN, WPAN, and WBANs), vehicular networks, underwater networks and machine-to-machine (M2M) communication among others.
Li-Fi can provide the military with high speed, non-detectable communications that cannot be identified through current direction-finding technology. The high-speed, multi-frequency communication capability inherent in Li-Fi can free up bandwidths used in critical legacy applications that haven’t converted to newer technology. With Li-Fi, inter-soldier, inter-vehicle, and inter-ship line-of-sight communications can render mobile units ubiquitous relays of information and orders without any verbal communication, while remaining totally invisible in the battlespace.
BT defence teamed up with pureLiFi to deploy LiFi in their Adastral Park Facilities a few miles from Ipswich. These facilities are home to approximately 3700 staff working on leading research and development.
The LiFi installation allowed for BT to test and prove unique use cases of LiFi for the defence sector. Applications such secure communications through light due to the intrinsically safe nature of containing light were established. Additional consideration was given to the ability to apply different security levels to individual lights or a group of lights allowing for very sophisticated geofencing.
DISA officials have shown interest and want to test LiFi technology. “Li-Fi technology has the potential of being faster than any radio-based technology existing at present,” Dr. Bill Butler, project lead for the DISA Li-Fi University Affiliated Research Center (UARC) Project, said in a DISA release. According to Dr. Butler, “light is already used for data transmission in fiber-optic cables and for point-to-point links, but Li-Fi is a special and novel combination of technologies that allow it to be universally adopted for mobile ultra-high speed internet communications using normal light frequencies across the 440 to 770 terahertz (THz) spectrum. However, Li-Fi can also be used in the non-visible frequencies, such as infrared, X-ray, and ultra-violet frequencies between 300 gigahertz (GHz) to 400 THz – presenting endless possibilities for manufacturing new and complex communication equipment.”
“It’s very high-speed bandwidth, very simple in terms of building out the network through the infrastructure that’s available,” said Rear Adm. Nancy Norton, DISA’s vice director.
“The ability to start and stop the network all is just based on breaking the light signal. You’ve got a light bulb, you’ve got a receiver, you put your hand in between and all connections stop. You remove your hand and they start again. So the ability to rapidly control who has access to a network in what would normally be a difficult-to-manage RF spectrum is really a significant deal.”
Lt. Gen. Alan Lynn, the director of the Defense Information Systems Agency noted that Li-Fi is attractive from a military perspective because, unlike Wi-Fi, it does not emit widely. Nor can it go through walls. It also relies on existing infrastructure. This can provide an advantage to ships at sea, he said, because it can enable non-detectable communications that cannot be identified through current direction-finding technology.
As a practical example, in the war-fighting domain if one is out in a tent in the middle of nowhere, using a light, it might be infrared but it is still light emitting that information you need, he said. “If somebody tries to come to jam you, they’re jamming RF, they’re not jamming that,” he said, offering that this could be a possibility for the future.
In a release, Butler said Li-Fi could be used for vehicle-to-vehicle communications through headlights or taillights without interference. “The data is secure because information is only transmitted to those in the line of direct sight,” he said. “It can also replace the complex cabling required in forward-deployed command centers by combining the network access points in the overhead lighting. This reduces power consumption and simplifies command center setups.”
Navy LiFi Requirements
The Navy is interested in using Li-Fi to improve submarine communications, since radio waves travel poorly under water and current acoustic communications are slow. The underwater VLC in the blue/green spectral range (450 nm-550 nm) is able to achieve data speeds of hundreds of Mbps for short ranges (less than a hundred meter) complementing long range acoustic communication.
LiFi can also be used to improve communication of Underwater Remotely Operated Vehicles,that operate from large cables that supply their power and allow them to receive signals from their pilots above. ROVs work great, except when the tethers aren’t long enough to explore an area, or when it gets stuck on something. If their wires were cut and replaced with light — say from a submerged, high-powered lamp — then they would be much free to explore. They could also use their headlamps to communicate with each other .
Submarine electronic warfare (EW) next generation architecture will require a variety of different connectivity solutions to enable its multi-layered architecture. Solutions range from high-speed networks (10GbE, 40GbE, 100GbE, and beyond) to more conventional speeds such as the well-known 1GbE which provides the vast majority of connectivity in today’s systems. There is potential to replace much of the 1GbE cabling if a secure, wireless system were implemented.
The solutions within VLC technology (Li-Fi included) are preferred in making use of existing incoherent Light Emitting Diodes (LEDs) for solid-state lighting as both transmitters and receivers in developing a VLC network.
With the concerns Wi-Fi presents, an alternate wireless network transport solution is desirable. Light Fidelity (Li-Fi) is a wireless networking system that provides data transmission through light and would reduce/eliminate EMI concerns, thus improving system performance/reliability. If additional signal strength is required, Li-Fi attocells have no interference from, and add no interference to, the radio frequency’s counterparts such as femtocell networks.
Li-Fi would appeal to not only the Navy but throughout commercial industries. With the reliable security it provides, this technology can be applicable to any application that is currently using Wi-Fi as its main source of data transmission. The technology’s advantage over Wi-Fi of not creating EMI would allow medical facilities, airplanes, or any location that would normally not allow Wi-Fi to use it.
Li-Fi is still in its development state where there has been a prototype designed, tested, and presented but not finalized. This technology will need additional research and development (R&D) to prove and demonstrate its effectiveness and reliability within/exceeding a 4-meter range.Development of a secure, high-speed, energy- and cost-efficient VLC prototype device will assist the Navy in reducing the increasingly larger burden of cable management with respect to Ethernet connectivity.
PHASE I: Develop a concept for a Li-Fi system in a system with the capabilities of transmitting data using light instead of radio frequency. Demonstrate the feasibility of the concept through either modeling or simulation in meeting the Navy needs and establish that the concept can be developed into a useful product for the Navy.
PHASE II: Based on the result of Phase I and the Phase II Statement of Work (SOW), develop and deliver a prototype of a system with the capability to transmit data from a light source to an electronic device. Evaluate the prototype to determine its capability in performance, either equivalent or exceeding that of Wi-Fi in terms of transmission rate and throughput.
In completion of Phase I, the company will develop a prototype to be tested and validated against Phase I model or simulations. Prepare a Phase III SOW to transition the technology developed for Navy use.
PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the technology for Navy use. Develop a system according to Phase III SOW for evaluation to determine effectiveness in an operational relevant environment. Support the Navy for test and validation to certify and qualify the system to be transitioned into the AN/BLQ-10B (V) program.