This is the second part of the series “Communication Protocols in IoT”, the first part can be found here
NFC or “Near Field Communication” is a wireless technology that is used for communication over extremely small distances (WPAN category, for NFC we are talking in terms of centimeters). While “NFC” sounds like one unified technology, it could when taking a closer look more be viewed as a collection of protocols and sub-standards that lets you design your product to your needs.
Technicalities and standards
NFC is one of many defined RFID (Radio Frequency identification) standards and operates in the 13.56 MHz ISM-band. The base standard for NFC physical layer and RF is ISO-18092 (Near Field Communication) while parts of an older ISO-14443 (Contactless integrated circuit cards) are also fully inherited or reused.
On top of the bottom layers, it immediately gets more interesting and diversified when different manufacturers and organizations have defined different protocols all the way up to the application layer.
[Image source: https://upload.wikimedia.org/wikipedia/commons/3/33/NFC_Protocol_Stack.png]
While not every protocol is interesting to cover in detail in a brief overview, it is worth mentioning that that tag types (1-4 and MiFARE) and the NDEF (NFC Data Exchange Format) are very central when working with NFC in order to read, write and interpret data.
The NFC technology can work in both active and passive mode where the passive mode is the most well-known one (think of reading data from an NFC tag/card). In this mode, NFC uses induction between the two communicating devices which gives the very nice property of one device (initiator) powering the other device. This means that a tag/card (target) does not need its own power source but is instead powered by the other device and transmits data by modulating the already generated electromagnetic field.
NFC can also operate in active or “peer-to-peer” mode where both devices have a power source and alternates between generating an RF field (sending) and being passive (receiving).
In terms of data transfer speed, NFC is not designed nor used to shuffle large amounts of data. A few different standards and modulation exist which allows NFC to transfer data with a bit rate of 106, 212 or 424 Kbit/s respectively.
Despite being a wireless technology with an extremely short range and limited transfer speed, there are quite a few use cases where NFC is a suitable and widely adopted technology:
- Contactless payment
A large use case today which currently is seeing large penetration in quite a few markets. This appears in many forms, everything from public transport access cards and NFC enabled credit cards to cellphone-based payment apps.
With a very low cost for NFC tags/stickers, it’s a very efficient way of storing identification data. Everything from single shirts in a store, car parts in a factory to large containers can carry their unique information with them through the supply chain in a small and cheap tag. The fact that the only thing you need to access/read the data is a semi-modern smartphone also gives this use-case quite a boost.
- Access control
The traditional badge or access card, while of course not every implementation of RFID based access control is based on the actual NFC standard. It’s easy to see why it’s a popular and fine-grained solution. Compare it to having physical keys or a key panel where a lost key/code could be very costly and/or unsecure (even with a unique code per user). An NFC card allows for instant revocation of access as well as a possibility to log who is accessing a secure/limited area at a certain time at a low cost.
A quite popular use case today where NFC is used to bootstrap and simplify the setup of other wireless technologies such as Bluetooth and/or WiFi. Instead of manually struggling with pairing processes, scanning, and manual key entry, simply bring the devices to close together and setup is complete.
A growing use case today, NFC can (and is) used in everything from labeling lab samples to reading your blood glucose levels with your cell phone.
Do you have questions about NFC technology or its use cases? Drop us an email at firstname.lastname@example.org or post in any of our social media channels.
// Erik Dahlgren