Near Field Communication

Most of you are already aware of NFC (Near Field Communication) technology and many of you might have used this technology in your smartphone or tablet for sharing photos with friends, and perhaps you might have used this technology for pairing the Bluetooth speakers and smartwatches. And in fact, because of this technology, we are able to use payment services like Google Pay, Apple Pay, and the Samsung Pay.

Near field communication

   So, this NFC stands for Near Field Communication. And as its name suggest, it is short distance wireless communication technology. So when two NFC enabled devices are very close to each other, roughly around 4 cm, then they can communicate with each other using the radio waves. Now, out of the two communicating devices, at least one device has to be an active device like a smartphone, tablet or payment terminal. While the other device active or passive and the example of a passive device is the NFC tag. Now, here the active device means the device requires the external power supply. While the passive device doesn’t require any external power supply and it is powered by the Electromagnetic field of the active device.

How NFC works and communicates with each other?

After having a little background about NFC(Near Field Communication), now, let’s understand how NFC works and how NFC devices can communicate with each other. So, like I said earlier, these NFC enabled devices to communicate with each other using the radio waves and these radio waves are generated using the antenna. So, if you take the case of a smartphone, then the antenna is fitted on the battery or sometimes it is fitted on the back side of the back cover.
   While in the case of the NFC tag, if you tear down the tag, you will find the antenna pattern. So, using these antennas, devices are able to communicate with each other.

Modes of Communication

   These NFC(Near Field Communication) supports the three modes of communication.

  • Card Emulation Mode.
  • Peer-to-Peer communication mode.
  • Reader or Writer mode.

  • Peer-to-Peer Communication Mode

So, first, let us talk about the Peer-to-Peer communication mode. The Example of this mode is when we are sharing the information using the two smartphones. Now, in this mode, both devices are active devices. And they can communicate with each other by generating the radio waves alternatively. It means that when one device transmits the data at that time the second device only listens to it. And it does not generate its own radio waves. Similarly, when the second device transmits the data, at that time the first device only listens to it and it does not generate its own radio waves. In this mode of communication, both devices generate the radio wave alternatively at the carrier frequency of 13.56 MHz by which they can share files and information with each other.

  • Reader and Writer Mode

Now, let’s talk about the Reader or Writer mode. An example of this mode is when we are accessing the data or information using the smartphone from the NFC tag. So, in this mode of operation is very similar to the RFID(Radio-Frequency Identification). So, in this mode, the active device like a smartphone or tablet reads or writes the data on NFC tag using the principle of Electromagnetic Induction. Now to read the information from the NFC tag, the active device generates the radio wave at the carrier frequency of 13.56 MHz. So, these waves used to get coupled to the antenna of the passive tag and from these electromagnetic waves, the NFC tag receives the power.
   So, this time-varying electromagnetic field generates the EMF or voltage in this passive tag. So, the generated voltage is rectified using the rectifier and it is used to power up the chip inside this NFC tag. Now, this small chip generally comprises the clock, EEPROM(Electrically Erasable Programmable Read-Only Memory), rectifier circuit and the smart controller. So, once the chip is powered up then the tag responds back to the active device by the technique, known as the load modulation. So, in this technique, the tag uses the internal clock of the chip and it generates the auxiliary carrier frequency of 848 kHz.
   Depending upon the stored data inside this chip, the load which is connected in parallel to the antenna is turned ON and OFF and in this way, data is sent back to the active device. In this way, by the principle of electromagnetic induction, the passive tag receives the power and using the load modulation the data is sent back to the active device.

  • Card Emulation Mode

Now, let’s talk about the Card Emulation Mode. These are used for mobile payments in our smartphones. So, in this mode, both devices used to be an active device. Generally, the one device used to be a smartphone and the second device obviously used to be the payment terminal. But in this mode, the smartphone acts as a passive smart card. So, they don’t generate or produce their own radio waves but they only respond to the requested data by the payment terminal. So, in this way, the smartphone acts as a passive device. So, the operating principle of Card Emulation Mode is very similar to the Reader or Writer mode.
   So, these are three supported modes of communication by the NFC(Near Field Communication).

Modes Of NFC(Near Field Communication)


Standards of NFC

   Now, in this NFC(Near Field Communication), some standards are defined to establish communication between the two devices. So, these standards are derived from the already existing standards which are used for radio communication. And these standards are known as the NFC-A, NFC-B, NFC-F, and NFC-V.

Applications of NFC

Now, let’ see some useful applications of the NFC. Many applications are already known to us. And in fact, we already using NFC for these applications. Like, for file sharing, for mobile payments, for pairing the different devices, and for information sharing using the smart posters and the business cards. But apart from that, it can be used for home automation, for health care, in the library system, or even for personal usage.
   So, at home, just by tapping the NFC tag using the smartphones we can change the brightness of the ambient light or it is also possible to change the temperature of the AC or even we can automatically close the doors using the NFC. So, these are some of the applications in which the NFC can be used at our home.
   Similarly, in healthcare, just by tapping the mobile to the patient’s NFC tag, you can get the required information and the history of the patient very quickly. Moreover, these NFC tags can be used for personal usage like, just by tapping the NFC tag, we can change the setting of our smartphone. So, just by tapping the NFC tag, we can turn ON the Wi-Fi or Bluetooth in our smartphone or even we can open a particular game or app.
   So, there are many Android apps are available using which it is possible to write on these NFC tags. The most popular among all is NFC Tools. So, using this app, it is possible to write on these NFC tags. In fact, it also shows the number of bytes that are required to write a particular code or URL in the NFC tag.
   And using another app called trigger, we can assign the different task which should be get performed once this NFC tag is detected. Like when we are in the car, then just by tapping the NFC tag, we can start navigation in our phone and once we reach the office then just by tapping the tag on the desk, we can turn the silent profile in our phone.
   So, these are some of the applications in which NFC(Near Field Communication) can be used.

Applications of NFC

Compare NFC with different technologies

Let’s compare NFC with technologies like Bluetooth, RFID, and the QR code.

  • Compare NFC with Bluetooth.

   Bluetooth is also wireless communication technology and using this we can share the information and file with the different devices. In fact, the data rate at which the information can be shared on Bluetooth is quite high compared to NFC. But in the case of Bluetooth, the time that is required for pairing the devices is more compared to NFC.
   In fact, in NFC two devices can be set up in less than 0.1 seconds and that’s why today in many devices NFC is used for pairing the different devices. And once the pairing between the device is established, then for communication either Bluetooth or Wi-Fi is used.

  • Compare NFC with the RFID.

   So, this NFC is derived from the RFID standards. In fact, the working principle of NFC is quite similar to the RFID. But these RFID works on different frequencies. Starting from the low frequency up to the ultra-high frequencies. But NFC works on the particular frequency band, which is a 13.56 MHz band.
   Now, in the case of RFID, the reader sends the request to the RFID tag and in response RFID tag replies back to the reader. So, we can say that there is only one-way communication is possible in the case of RFID. While in the case of NFC, it is also possible to have peer-to-peer communication. That means, two devices can communicate with each other alternatively.

  • Compare NFC with the QR code. 

   This QR code technology can also be used in some applications where these NFC tags are used. For example, using this QR code, we can open some applications or we can provide some additional information to the customer about the product. So, in a way, this QR code can also be used in place of NFC tags. But to access the information, we need to scan the QR code using mobiles. While in the case of NFC, just by tapping the mobile to the NFC tag, the information can be easily accessed.
   So, we can say that the access time which is required in the case of NFC is less than the QR code. Moreover, this NFC is more secure than the QR code, because, in the case of  QR code, it can be replaced by putting another QR code on the top of it. While in the case of NFC, if someone puts another NFC tag on the top of it, then neither of the tags can get accessed. So, in a way, NFC technology is more secure than the QR code.
   So, this is all about the comparison of NFC(Near Field Communication) with the different technologies.

   So, this is all about Near Field Communication (NFC), modes of communication, NFC standards, applications of NFC, and the comparison of NFC with different technologies. Now, what’s your opinion on NFC, let me know in the comments.

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