Follow us
Contact us

VLC - Visible Light Communication

What is LiFi ?

Internet of things (IoT) is progressively affiliated to our day-to-day life. The examples enlarge from smart connected homes to wearable to healthcare [1]. IoT applications not only just boost our comfort but also give us more control to reduce periodic work life and personal tasks [1]. Communication is the vital part of every IoT applications. Usually, the wireless communication lay on radio waves. In future, the need for bandwidth in radio spectrum will exhaust. The need for the alternative method is important. LiFi was invented by Dr. Harald Haas and successfully demonstrated at TED in 2011 [2]. Li-Fi is a visible light communication and subsidiary part of optical fiber communication [1]. Optical fiber communication uses coherent light sources and in LiFi use incoherent light sources [3]. The advent of light emitting diodes produce incoherent light, this can be a Li-Fi transmitter. There are many pros and cons for this technology. The entire radio spectrum communication can not replace by Li-Fi but there is a certain area that can reduce the use of radio waves such as near field communication, office or home applications, safe environmental conditions such as petrochemical plants etc [4]. This paper proposes a high-speed transmission technique through Li-Fi, which is called triplet Li-Fi. The common scenario uses a visible light source for bearing the data.

Visible light can be produced by RGB(red, green, blue) colors, it is meant to say that each spectrum can carry different data. The flickering of light is not visible to human eyes and it remains Li-Fi. Through this methodology, the Li-Fi can improve it’s capability by three times and can improve the physical layer security in communication.


Li-Fi is an added networking physical layer argumentation for current RF methods such as wireless fidelity (Wi-Fi) or long term evolution (LTE). In every Li-Fi source, LED is the bidirectional entry point for the downlink [5]. The uplink should not interpret the downlink, this can be an infrared light source [5]. The greatest fallacy of Li-Fi is a line-ofsight (LOS) link technology [6]. The figure 1 illustrates the perspective of Triplet Li-Fi. Visible light can be reversed into RGB. Each color packed with different data. Perfect ratio of RGB mix is achieved through heed current. Red and green spectrum convey the test sequence and it is generated by an astable multivibrator with 50% duty cycle. Blue spectrum can tote a computer generated binary data, which only permits transistor-transistor logic (TTL). The transmitter includes a simple receiver, a non-filtered photodiode in photovoltaic mode which makes it bidirectional. This operation does not deal with any kind of modulation technique. Greater attainments are feasible with modulation scheme such as orthogonal frequency division multiplexing (ODFM). This is the mild implementation of triplet Li-Fi which extends generously to the reader. The figure 2 illustrates depict of the triplet Li-Fi reception. Blended RGB can be discriminated by the colour filters which can feed to photodiodes. Packed data in blue spectrum must be severalized precisely. Implementation of the trans-impedance amplifier does the translation of photocurrent to the prime voltage level with edge frequency of 1.9Mhz. Preamplifier does the principle voltage for the buffer. Buffer deeds the two services in this case. It compromises the noise generated by capacitance effect in the photodiode and isolates among computer. This implementation does not discuss the
Figure 1
Figure 2


Triplet Li-Fi lengthens the adequacy of Li-Fi proficiency. Li-Fi is voluminous technology that can frame radical change in future. Li-Fi can be the key for IoT applications [9]. Li-Fi can furnish the 5th generation cellular technology and beyond. From many years light emitting diodes leading the lightening method and currently LED lighting are an integral part of the budding smart cities, as it can be Li-Fi spotlights. Li-Fi can eliminate complex routing of wires in offices and hospital applications. LED lighting can transfer the data so it will not expend additional space. Light has the catalytic property as it is an energy source.This property unfolds the wireless (solid-state drive)SSD/USB in the near field of communication(NFC) applications and more. Emerging mobile phones and computer displays, backlights or flashlight can remit the data. Triplet LiFi accredit appended security measures in physical layer communication that can employ additional security in digital payment applications.


While gathering about Li-Fi, there can be many misconceptions too. In broad, the Li-Fi operates in normal environment. Apparently, sunlight enacts a constant conflict signal to the Li-Fi reception and it is easily distinguishable from modulated light. Li-Fi serves frequency generally greater than 1Mhz. Hence, a constant sunlight easily drains out. Li-Fi is reorganized as physical layer communication. Therefore, the underlying existing communication protocols can be compatible in Li-Fi. Light can not penetrate any opaque objects. Thus it improves controllability and security. Power consumption of Wi-Fi router estimated that 2- 20 watts, with six watts being average. Power consumption of LED routers will be pretty much lower when it is flickering. There are many companies researching about Li-F and by 2020, Li-Fi will be a part of communication market in the industry.