NFC

Near Field Communication (NFC) allows two devices to communicate when brought within very short distances of each other - about 4 cm. It is a set of communication protocols that offer low speeds and simple setup. There is a variety of NFC protocol stacks depending on the type and use case.

NFC uses electromagnetic induction between two loop style antennas when devices exchange information. Data rates are around 100-400 kbit/s. It operates over radio frequency band 13.56 MHz, which is unlicensed and globally available.

There is usually a full NFC device, such as a smartphone, and an NFC tag, such as a chip reader. All full NFC devices can operate in three modes:

• NFC peer-to-peer: Devices exchange information on the fly.
• NFC card emulation: Smartphones can act like smart cards in this mode, allowing mobile payments or ticketing.
• NFC reader/writer: Full NFC devices can read information stored in inexpensive NFC tags, such as the type used on posters or pamphlets. You have probably used this at a conference to scan your attendee badge.

NFC tags are usually read-only, but it is possible for them to be writeable. There is an initiator device and a target device in NFC communications. The initiator device creates an RF field that can power a target device. This means NFC tags do not need batteries in what is called passive mode. Unpowered NFC tag devices are very inexpensive, just a few pennies.

There is also an active mode where each device can communicate with the other by alternatively generating its own field to read data, then turning it off to receive data. This mode typically requires both the devices to have a power supply.

For data records that eventually end up in an analytics dataset, the full NFC device would act as a gateway, translate the message, and then communicate over a different network protocol stack. In the case of a smartphone, it would take the NFC tag data and create its own data message to send over 4G/LTE for a destination on the internet.