The purpose of this paper is to particularize the historical, science and technological impact of Li-Fi, to also include the vast reaching context of this incredible point in the wireless timeline. The paper seeks to establish the historic background of the Li-Fi technology as well as its technical working. The possibilities of Li-Fi extend to the application in military and undersurface communication operations. Traffic Management is another area where LED will be of great use. Li-Fi can be used in LED lights traffic managements. Other areas where Li-Fi will be ideal include disaster management, remote location positioning and dead zone areas management.
Li-Fi (Light Fidelity)
Background Introduction
Light fidelity (abbreviated as Li-Fi) is a technology, which transmits data through illumination. The data is sent via LED light bulbs with varying intensity. The light intensity is faster that the human eye capability to follow under normal circumstances. The technology is an alternative of the current Wi-Fi technology. At the science level, the technology is a wireless communication with the high-speed and bidirectional network. It can also be said to be a visible light communication or optical wireless communication (OWC). According to Antony and Verma (2016) the basis of Li-Fi is Visible Light Communication (VLC). The data communication applies visible light between (but not limited to) 400THz (780nm) and 800 THz (375 nm). This range is the optical carrier for data transfer and illumination. Fast light is used in information transmission in a wireless tunnel. The connection includes a white LED (transmission source), silicon photodiode and a viable response to visible light and receiver.
2. Rationale for Creation of Li-Fi
Li-Fi was created so as to overcome the current radio-based and relatively limited wireless spectrum. The creation aims at promoting high-speed optical wireless systems. The proposal was made by Harald Haas, a German physician. The technology has been preferred by the developers as high density and wireless data coverage. It can be ideally operated in confined areas. Also, Li-Fi has the capability of easing the radio interference technicalities. The factors that make the technology preferred and promoted encompass better efficiency, effectiveness and speed (Dimitrov & Haas, 2015).
With Li-Fi, wider bandwidth and effectiveness in the application is achieved. Also, the technology has a higher security cover than Wi-Fi. The laboratory tested prototype connection has resulted in ideally high-speed connections (Condliffe, 2011). In matters concerning costs, Li-Fi is more cost effective and economical than the current Wi-Fi connection. LED’s are naturally low cost and present many lighting units opportunities. The full range application
3. How Li-Fi Works
Li-Fi works with a set-up of a light emitter and photo detector. The light sensor registers definite designations on the status of the LED. Binary one means it is on, and binary zero means LED is off. Data encoding is done by varying the LED light flickering rate. Different 1s and 0s strings are then generated. The LED bulbs have the very high intensity which cannot be noticed by the human eye. Light emitting diodes are employed in the on and off switching. The on and off activity of the LED bulb enables the data transmission in binary codes. Switching on and off the LED gives a logical ‘I’ and ‘O’ respectively. The pulse rapid application of light to transmit information in a wireless form refers to the visible light communication (VLC).
As long as there is one device having the photodiode and a light source, which processes signal, Li-Fi can work. The photodiode must however, have the capacity to receive light signals, and the light signal has a unit for signal processing. The size of a Li-FI system determines the rated output of the system. A big system will require a high rate light output. LED as a semi-conductor of the light source can cause the amplification (of the rapid switch) light intensity. Also, modulation of multiple signals is made possible where binary data is used. One cab uses and applies the applications of audio, the web, video and other, online media in an internet enabled device.
A. Reason for Li-Fi
The reason for the use of Li-Fi is to increase efficiency, effectiveness and speed of data and internet connectivity. The technology has been proposed due to its ability and potential to produce data rates that exceed the 10 megabits per second bit. The speed exceeds the current broadband connection. Currently, there are the challenges of internet access and speed within a single network. As multiple devices become connected to a single network, the speed goes down significantly. Li-Fi connectivity by illumination of LED light bulbs uses optical version of Gigahertz radio waves making it faster. At an advanced stage, the Li-Fi technology can be used to connect multiple media and devices in a single LED lit room. The technology also offers high security protection. Only those who can see and access the illumination can access the data. The prospects for military area security application are also high. Such areas have great communication security prioritization.
Li-Fi is needed to cover those areas where Wi-Fi technology has no presence. It is also necessary where Wi-Fi is currently inapplicable due to technical and security issues. Currently, hospitals and aircraft do not allow Wi-Fi. Using Wi-Fi leads to interference with radio waves and consequently, the operations of these institutions. When applied, Li-FI will be used in all these private and public areas. In the Education sector, institutional use of Wi-Fi makes the data transfer to be very slow. Li-Fi using LED light will enable fast and efficient speeds for all staff and learners. In the medical field, operation theatres (OTs) will be able to access internet and data transfer efficiently.
Li-Fi can be used without the fear of radiation concern. OT will be made tech savvy by remote medical control and robotic surgeries. Air flight passengers will be able to access the low-speed internet at very high rates. Overhead reading bulbs and other light sources can be used as Li-Fi internet sources. The remotely operated vehicles (ROV) operation will be boosted in a major way by this technology too. The cable tethering for power and signal used in ROV’s is not long enough to allow larger areas exploration. Replacing the wire connection with submerged high powered light sources of light can be very economical and effective. Headlamps can be used to communicate and process data in an anonymous way.
II. Technological Implications
A. Technological implications of Li-Fi
1. Mobile devices and Li-Fi
Mobile devices can use Li-Fi as long as they are built with the capabilities. Some iPhone handsets have a Li-Fi reference code written inside. Integration of Li-Fi with mobile phones would include the encoding of data in force of the discharged light as part of the discharged light. The usual radio waves are replaced by light waves in light discharge diodes.
2. Government involvement
The government’s involvement in the li-fi technology is mostly in the allocation of bandwidth. The Federal Communications Commission in America regulates and allocated the spectrum portions and bandwidths. The FCC has in the past reported that the bandwidth capacity used by the Wi-Fi domain is almost used up (Sarika, Himanshu & Gaurav, 2013). To open up more space for data transfer, the commission and other federal regulation bodies have considered adoption of Li-Fi.
3. Security Concerns
The security concerns associated with Li-Fi are in the range of the signal transmission. The limited range means internal and external sharing of the same sensory source can be impeded. In the case of a security circuit relying on a single source, this can be a major drawback. Additionally, the need to keep lights on at all times causes security problems. Power outages or cuts will mean sudden interference from the network system. Where immediate backup does not exist, this situation can lead to a serious security breach. Deliberate or accidental power cut can result in the abrupt cut and disruption of a security installation. During night time, people might prefer lights off to sleep or for privacy concerns.
At the same time, the people might require being connected online in social media, chatting platforms or online games, videos and general web surfing. It would, therefore, mean keeping the lights on or dimming them to maintain a network connection. Again, this light can be a security concern as surveillance in military or high-security installations require some level of darkness anonymity at night. Dimming lights at night or for energy saving might also cause another security problem. Dimming LED source lights to mean the VLC outreach signal will weaken. Thus the network and data transfer become slower. The slow data connection can lead to delayed response time. Such applies in instances where security alarms, lights, communication and signals all rely on the LED VLC system. The result would be reduced network system efficiency and as a result reduced network connection reliability.
Remote detection is still a problem in Li-Fi. In 2012, a pilot test revealed that the technology was detectable up to a distance of ten meters. As a result, there is a high possibility that the system can be hacked and compromised. The implication is that password integrity could be a huge security scare where devices with higher detection power are applied. Close or parallel devices and operators such as stationery stations can be used to launch network attacks from the 10 meter distance. The other security concern on Li-Fi is the inability to be used in system collaboration of moving objects. Thus, it would be very hard for a Li-Fi system to be able to read data or access other internet data connection in a moving vehicle. Other areas where Li-Fi connection to external reading encoding would be on fast moving trains, planes, running persons, water vessels among others.
III. The Science of Li-Fi
A. Pulsing light code transmission through open areas
I. Binary codes
Binary codes are used in Li-FI to transmit Visible Light Communication (VLC). The binary codes transmit light in the ranges of 400 to 800 terahertz (THz). The speeds are very high and not detectable by the naked human eye. The speed is 100 times higher than the current systems involving the Wi-Fi connection. In the laboratories, the Li-Fi has been seen to have speeds hitting above 200gbps (Gado & El-Moghith, 2015). Such would be expected to increase and improve with time as more R&D is done. Switching on and off the binary codes (Is and Os) cause the creation and encoding of messages. Multiple or high-speed switching of the binary codes leads to the multiple messaging. Also, the system allows for the creation and use of colored (in multiple systems) lights. Such leads to varied and broad spectrum message encoding and decoding.
II. Refraction
Refraction of the LED light can be applied in Li-Fi to achieve feasibility limits overcoming. The light can work in reflected surfaces to bring about the line of sight distortion realization. Such would be more used and needed where the light is used beyond one room. Dim light would be used in a space of room (or two as per the context) in a controlled environment. Non-coherent light is then applied in the natural spreading of refraction and reflection of light. It would be important to ensure consideration of atmospheric conditions. Certain atmospheric conditions, such as foggy and smoky rooms might limit or lower the limits of brightness on light penetration from refraction. Thus, beyond a few meters, refraction might be greatly limited. It would also be dependent on the surface refractions being used in the room for the successful signal decoding to take place.
Masterson (2014) explains that visible light can be interchanged and infrared light used from a photo detector. As a bidirectional communication system, a mobile device which is internet enabled can be connected to the LED system and data sent back and forth. In such a connection, source download and uplink is possible. Multi colored RGB are also possible engineered LED’s that can apply refraction successfully. The red, green, and blue retina size can be applied to wide range signal as opposed to single colored phosphor-coated white LED.
B. Visible Light Communications (VLC)
Visible Light Communication (VLC) also known as D-Light is applied in production of higher data rates. Over 10 megabits per second can be produced using this format. It is higher than the average broadband connection. VLC can therefore be recognized as an IM/DD framework. The balance signal must as a result be genuine and uni-polar (non-negative). VLC usually makes use of visible light in signal transmission (Nitrutti & Nimbalkar, 2013). There are some specially designed electronic devices which have photodiode in them enabling the receivership of signals in light sources. Basic digital cameras and cell phones have been used successfully in signal receivership too.
VLC is applied in ubiquitous computing due to the prevalence of devices emitting light are readily available in public. Ordinary lamps are as a result used in signal transmission o g 10kbit/s. LEDs can also be applied in areas of 500Mbit/s. Such is at the same distance or longer where LEDs with higher potential are used. Multi-channel signal transfer such as an equivalent of one channel to one pixel can be used in spatial awareness. Single photodiodes are also used in the image sensors. The VLC technology can be trace back to the invention of the photo phone by Alexander Graham Bell. The technology was used in the transmission of speech modulated sunlight. Recent inventions have led to the increase and widening of the transmission capability as well smart light engineering. Companies such as Siemens and Henrich Hertz Institute have widened the LED transmission. There is a standardization of the VLC protocol using the IEEE Wireless Personal Area Networks.
C. Room Restriction
Li-Fi is restricted to the access of light and the solid room partition. The Li-Fi light used in the connection is the equivalent of the Morse code. It can therefore be said to have the potential to have a faster and secure network when used in that context. Less interference is also attained with the limitation (Sodhi & Jeslin, 2015). The room restriction is therefore more of a benefit than a demerit. The VLC cannot penetrate walls and thus offers a much shorter range. This range increases protection from hacking and eavesdropping/man-in-the-middle attacks.
References
Antony, J., & Verma, P. (2016). Exploration and Supremacy of Li-Fi over Wi-Fi. IJCATR, 5(2), 83-87. http://dx.doi.org/10.7753/ijcatr0502.1008
Condliffe, J. (2011). Is Li-Fi ready to establish itself as the new Wi-Fi? New Scientist, 211(2822), 18. http://dx.doi.org/10.1016/s0262-4079 (4079 (11)61753-3
Dimitrov, S. & Haas, H. (2015). Principles of LED Light Communications. Cambridge University Press: Cambridge.
Gado, M., & Abd El-Moghith, D. (2015). Li-FI Technology for Indoor Access. Saarbrücken: LAP LAMBERT Academic Publishing.
Masterson, V. (2014). New center signals a bright future for Li-Fi industry in the UK. Infinite Magazine, Vol. 3 Issue 2013-2014.
Nitrutti, D., V. & Nimbalkar, R. R. (2013). Light-Fidelity: A Reconnaissance of Future Technology. International Journal of Advanced Research in Computer Science & Software Engineering, Vol. 3 Issue 11, Nov.
Sarika, A., Himanshu, S. & Gaurav, R. (2013). Li-Fi (Light Fidelity) Technology. International Journal of Engineering Research & Technology (IJERT), Vol. 2 Issue 11, Nov.
Sodhi, A. & Jeslin, J. (2015). Light Fidelity (LI-FI) – The Future of Visible Light Communication. International Journal of Engineering Research and General Science, Vol. 3 Issue 2, Mar.-Apr.
