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LiFi vs WiFi-Basic difference between LiFi and WiFi

This page compares LiFi vs WiFi describes basic difference between LiFi and WiFi technologies. LiFi stands for Light Fidelity and WiFi stands for Wireless Fidelity. The comparison between LiFi vs WiFi is done based on their features, working operation, merits, demerits, applications etc.

Introduction:
Both LiFi and WiFi technologies are mainly used for internet based applications. LiFi uses light as medium for data communication where as WiFi uses Electromagnetic waves for data communication. LiFi is optical communication technology where as WiFi is radio communication technology. Let us understand them individually before we derive difference between them.

LiFi Technology

Li-Fi internet architecture

Following are the features of LiFi technology as depicted in the figure-1.
• LiFi (Light Fidelity) works based on VLC (Visible Light Communication) principle.
• LiFi transmits data using light intensity modulation.
• It uses LEDs at transmit ends and Photo-detectors at receive ends. LiFi dongle uses photo-detectors as shown in the figure-1. Here LEDs are connected with internet server via lamp driver for internet connection.
• It uses light with wavelength ranging from 380 nm to 780 nm for data communication between LEDs and photo detectors.
• LiFi system supports three modes viz. peer to peer, star and broadcast.
• LiFi system uses modulation schemes such as OOK, VPPM, CSK.
• The PHY and MAC layers of LiFi system are defined in IEEE 802.15.7-2011 standard.
• LiFi technology is used for various applications which include street lights, sign boards, internet etc. • It transfers data very rapidly and securely due LOS (Line of Sight) operation of optical signals. Refer LiFi tutorial >> for more information.

WiFi Technology

WiFi internet architecture

Following are the features of WiFi technology as depicted in the figure-2.
• As shown WiFi AP (Access Point) or Router is connected with internet broadband cable or with cellular network. All the wifi compatible mobile phones, tablets or laptops are connected with AP (or router) to obtain internet.
• WiFi network operates in either of two modes viz. adhoc (i.e. BSS-Basic Service Set) and infrastructure (i.e. ESS-Extended Service Set).
• In BSS WLAN compliant stations (i.e. STAs) communicate directly. In ESS WLAN compliant STAs communicate with APs (Access Points) to access internet.
• WiFi supports different speeds and coverage ranges as per implemented standard in the devices (STAs, APs). 802.11a supports upto 54 Mbps, 11b upto 11 Mbps, 11n supports 72 Mbps/150 Mbps as per BW (20MHz/40MHz), 802.11ac wave-1 supports upto 1.3 Gbps (80MHz, 3 streams, 256QAM), 802.11ac wave-2 supports upto 3.5 Gbps (160MHz, 4 streams, 256QAM) etc. The distance coverage of 70 meters (indoor) to 250 meters (outdoor) can be achieved.
• WiFi network operates in different frequency bands viz. 2.4 GHz, 5 GHz.
• The PHY and MAC layers of WiFi system are defined in IEEE 802.11 standards. There are various versions of 802.11 which include 11a, 11b, 11g, 11n, 11ac etc. Refer WLAN tutorial >> for more information.

Compare LiFi vs WiFi | Table of Comparison between LiFi and WiFi

Following table compares LiFi vs WiFi and derives difference between LiFi and WiFi technologies with respect to various features.

Feature LiFi WiFi
Full form Light Fidelity Wireless Fidelity
Operation LiFi transmits data using light with the help of LED bulbs. WiFi transmits data using radio waves with the help of WiFi router.
Interference Do not have any intereference issues similar to radio frequency waves. Will have intereference issues from nearby access points(routers)
Technology Present IrDA compliant devices WLAN 802.11a/b/g/n/ac/ad standard compliant devices
Applications Used in airlines, undersea explorations, operation theaters in the hospitals, office and home premises for data transfer and internet browsing Used for internet browsing with the help of wifi kiosks or wifi hotspots
Merits(advantages) Interference is less, can pass through salty sea water, works in densy region Interference is more, can not pass through sea water, works in less densy region
Privacy In LiFi, light is blocked by the walls and hence will provide more secure data transfer In WiFi, RF signal can not be blocked by the walls and hence need to employ techniques to achieve secure data transfer.
Data transfer speed About 1 Gbps WLAN-11n offers 150Mbps, About 1-2 Gbps can be achieved using WiGig/Giga-IR
Frequency of operation 10 thousand times frequency spectrum of the radio 2.4GHz, 4.9GHz and 5GHz
Data density Works in high dense environment Works in less dense environment due to interference related issues
Coverage distance About 10 meters About 32 meters (WLAN 802.11b/11g), vary based on transmit power and antenna type
System components Lamp driver, LED bulb(lamp) and photo detector will make up complete LiFi system. requires routers to be installed, subscriber devices(laptops,PDAs,desktops) are referred as stations

Following table-2 mentions difference between VLC and Wifi wireless technologies. As we know LiFi technology is based on VLC principle. This will help reader to understand the difference between LiFi and WiFi in more detail.

difference between VLC and WiFi

Conclusion of LiFi vs. WiFi:
• LiFi technology is not replacement of widely used wifi technology. Both the technologies LiFi and WiFi co-exist together based on their respective unique features.
• LiFi operates between wavelengths in the range from 380 nm to 780 nm. WiFi operates at different frequency bands viz. 2.4 GHz and 5 GHz.
• LiFi is used to exchange data incredibly rapidly and securely at much lower power level compare to WiFi.



LiFi and WiFi Related Links

LiFi internet vs WiFi internet
Data Over Light basics mentioning how Li-Fi works
WiFi Internet using WiFi hotspots
MiFi vs WiFi
WiFi RF Channels
LiFi tutorial

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