NFC Near Field Communication

- a summary overview or tutorial of Near Field Communications NFC, the contactless form of short range communication being used in mobile phones, electronic devices and payment cards.

This Near Field Communications, NFC tutorial is split into several pages each of which addresses different aspects of NFC operation and technology:

There is a growing number of applications where a form of very short range wire-less communications is needed. One technology that can meet this need is called Near Field Communications or NFC.

NFC near field communication is able to provide contactless communication over short ranges, typically up to about 4 or 5 centimetres. In this way it is able to provide connection simply by placing the two devices requiring connection close together.

As no physical connectors are used with NFC near field communication, the connection is more reliable and does not suffer problems of contact wear, corrosion and dirt experienced by systems using physical connectors.

NFC applications

NFC technology has evolved from a combination of contactless identification and interconnection technologies including RFID and it allows connectivity to be achieved very easily over distances of a few centimetres. Simply by bringing two electronic devices close together they are able to communicate and this greatly simplifies the issues of identification and security, making it far easier to exchange information. In this way it is anticipated that Near Field Communications, NFC technology will allow the complex set-up procedures required for some longer range technologies to be avoided.

Near field communication NFC lends itself ideally to a whole variety of applications. These include:

• Mobile phones, PDAs, etc
• Personal computers
• Check-out cash registers or "point-of-sale" equipment
• Turnstiles
• Vending machines
• Parking meters
• ATMs
• Applications around the office and house, e.g. garage doors, etc

A further application that was proposed was that NFC connections could be used to configure the connection between two wireless devices. All that was required to configure them to operate together wirelessly would be to bring them together to effect the NFC "connection". This would initiate the a set-up procedure, communication could take place over the NFC interface to configure the longer range wireless device such as Bluetooth, 802.11 or other relevant standard. Once set up the two devices could operate over the longer range allowed by the second communication system.

NFC near field communication is ideally placed to provide a link with the contactless smart card technology that is already used for ticketing and payment applications. It is broadly compatible with the existing standards that have been set in place. Accordingly it is quite possible that NFC enabled devices could be used for these applications as well.

There are many other applications for near field communications, NFC. These could include general downloading data from digital cameras or mobile phones, as well as any other data communication required between two devices.

Beginnings and NFC forum

Near Field Communication Technology, NFC has many of its roots in the RFID business. Some of the basic ideas came directly from RFID work that had been previously undertaken. Now Sony and Phillips have taken the lead and jointly developed the technology. It follows on from their proprietary smart card protocols and can be seen as an initiative to move forward the contact-less ticketing and payment applications that are seen as the next stage in this market. The standard for the technology was approved as an ISO/IEC standard on December 8 2003, having been approved earlier as an ECMA standard. The next stage in the standardisation process came when Nokia, Sony, and Phillips formed the NFC forum on 18th March 2004.

The NFC forum grew quickly and in 2008 there were over 150 members comprising manufacturers, applications developers, financial services institutions, etc.

In June, 2006, the NFC Forum formally outlined the architecture for NFC technology. In August, 2006, the NFC Forum released the first four Forum-approved specifications. These NFC specifications set in place a "road map" to enable interested parties to create their own products.

NFC basics

NFC Near Field Communication provides short range wireless connectivity and has developed out of the RFID style contactless identification and interconnection technologies. The concept of NFC near field communication is that the technology is able to provide a very easy method of providing connectivity between devices that are a few centimetres apart, and without the need for all the security and set-up procedures that are needed for many other communication technologies.

NFC near field communication is a wire-less technology, using radio frequencies. It operates at a frequency of 13.56 MHz within the globally available and unregulated 13.56 MHz frequency band. As a result no licenses are required for operation on these frequencies.

In addition to this the radio transmissions using NFC are half duplex as the same channel is used for both transmit and receive. Also to prevent two devices transmitting together, they operate what is termed a listen before talk protocol. The devices may only transmit if they previously listen to check that no other devices are transmitting. In view of the short ranges involved, the protocol used by NFC need not be as comprehensive as that used for toher wireless protocols.

Connection is made between two NFC devices when they are brought together so there is no difficulty in associating two devices. This occurs when the two devices are brought to less than about 4 centimetres of one another, although actual distances will depend upon a variety of factors, and figures of 20 centimetres for the maximum communications distance have been seen. In this way a simple wave or touch can establish an NFC connection. Because the transmission range is so short, NFC-enabled transactions are inherently secure.

To provide the standard interfaces, the underlying layers of NFC technology follow the normal ISO standards.

The data transfer rate may be either 106, 212 or 424 kbps. The application itself sets up the initial communication speed, but it may be changed later dependent upon the communication environment and the requirements.

The NFC near field communication standard defines two types of NFC device. These are known as the Initiator and Target of the communication. As the names imply, the initiator is the device that initiates the communication and it controls the data exchanges. The Target device is the one that responds to the requests from the Initiator.

• Active mode of communication:   In the active NFC mode of communication, both devices generate an RF signal on which the data is carried.
• Passive mode of communication:   In this mode of communication, only one NFC device generates an RF field. The second passive device which is the target uses a technique called load modulation to transfer the data back to the primary device or initiator.

In addition to the NFC modes of operation, three communication modes are also defined:

• Read / Write:   This mode of operation within NFC near field communication allows applications to transfer data in an NFC Forum-defined message format. It should be noted that this mode is not secure. It is also necessary to note that this mode is supported the Contactless Communication API
• NFC card emulation:   This NFC mo enables the NFC device to behave as a standard Smartcard. In this mode, data transfer is secure and the mode is also supported by the Contactless Communication API.
• Peer to peer:   A third mode within NFC is the peer to peer mode which supports device to device link-level communication. It is worth noting that this mode of NFC communication is not supported by the Contactless Communication API.

Standards and capability

With Near Field Communications set to become widely accepted in many applications, the system has been standardised by a number of globally accepted standards bodies. NFC has standards accepted by ISO (18092), ECMA (340) and ETSI. Additionally NFC is compatible with Philips' MIFARE® (ISO 14443 A) and Sony's FeliCa smart card protocols.

Summary

Although Near Field Communications, NFC, may at first sight appear to be, "just another wire-less system", or similar to RFID this is not the case and it appears that it will find a number of applications. Applications are now becoming more widespread and further applications are following on.

Further pages from this tutorial
Page [ 1 ] >> [ 2 ] >>
Next >>