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Li-Fi

Li-Fi (Light Fidelity) uses LED (Light Emitting Diodes) to transfer data. It pulses LEDs so quickly that the human eye simply sees light and detects no flickering. This technology requires line-of-sight between the LEDs and the sending/receiving devices. Li-Fi is used in areas where wired devices are not (easily) used, and in areas where electromagnetic interference (EMI) makes traditional wireless technologies such as 802.11 or Bluetooth difficult or impossible to use. Traditional wireless radio technologies can also risk interfering with critical equipment, such as some medical equipment or devices. Hospitals often face all these challenges.

Light has considerably more potential bandwidth than radio waves, so Li-Fi can transmit at over 100 Gbps, faster than any current Wi-Fi technology:

“LiFi is a Visible Light Communications system transmitting wireless internet communications at very high speeds. The technology makes a LED light bulb emit pulses of light that are undetectable to the human eye and within those emitted pulses, data can travel to and from receivers. Then, the receivers collect information and interpret the transmitted data. This is conceptually similar to decoding Morse code but at a much faster rate—millions of times a second. LiFi transmission speeds can go over 100 Gbps, 14 times faster than WiGig, also known as the world’s fastest WiFi” [14].

RFID

Radio Frequency Identification (RFID) is a technology used to create wirelessly readable tags for animals or objects. There are three types of RFID tags: active, semi-passive, and passive. Active and semi-passive RFID tags have a battery. An active tag broadcasts a signal; semi-passive RFID tags rely on a RFID reader’s signal for power. Passive RFID tags have no battery, and also rely on the RFID reader’s signal for power.

Active RFID tags can operate over larger distances. Devices like toll transponders (allowing automatic payment of highway tolls) use active tags. Passive RFID tags are more inexpensive; they are used for applications such as tracking inventory in a warehouse.

RFID signals may be blocked with a Faraday Cage, which shields enclosed objects from EMI. Electricity will seek to go around a conductive object rather than through it (like lightning hitting a car: the occupants inside are usually unharmed). A Faraday Cage is a metal cage or enclosure that acts as the conductive object, protecting objects inside. This blocks many radio signals, including RFID. The cage can be as simple as aluminum foil wrapped around an object.