{"id":396,"date":"2018-10-03T14:12:00","date_gmt":"2018-10-03T12:12:00","guid":{"rendered":"https:\/\/www.scionova.com\/?p=396"},"modified":"2018-10-03T17:41:10","modified_gmt":"2018-10-03T15:41:10","slug":"communication-protocols-in-iot-part-2","status":"publish","type":"post","link":"https:\/\/www.scionova.com\/en\/communication-protocols-in-iot-part-2\/","title":{"rendered":"Communication Protocols in IoT – Part 2"},"content":{"rendered":"

This is the second part of the series “Communication Protocols in IoT”, the first part can be found here<\/a>\u00a0<\/em><\/h4>\n

NFC
\n<\/strong>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.\u00a0\u00a0<\/span><\/p>\n

Technicalities and standards<\/strong>
\nNFC 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.
\nOn 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.\u00a0\u00a0<\/span><\/p>\n

\"\"[Image source: https:\/\/upload.wikimedia.org\/wikipedia\/commons\/3\/33\/NFC_Protocol_Stack.png]<\/p>\n

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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.\u00a0<\/span><\/p>\n

Protocol Basics<\/strong>\"\"<\/h3>\n

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.\u00a0<\/span><\/p>\n

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).\u00a0<\/span><\/p>\n

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.\u00a0\u00a0<\/span><\/p>\n

Use Cases
\n<\/strong>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:<\/p>\n