NFC Wireless Communication Specifics

By Robert R. Sabella

Before you can define the niche that Near Field Communication (NFC) occupies in the pantheon of wireless technologies, you must know how NFC communication works to some degree. The following discussion provides you with details about how NFC works as a wireless communication technology, so that you can better understand why NFC is such a great technology for private or personalized communications of all sorts.

Understanding selectivity

The term selectivity, when used in the context of NFC, means being able to ensure that a reader reads only the card you want to target. The reader and the card need to be close enough together to allow Radio Frequency (RF) communication between the two.

If the reader read every card in the area, you would have a problem deciding what content to use or you might have to deal with a wealth of mixed content coming from all the cards simultaneously. Of course, the cacophony of information might be interesting for a little while, but you’d soon grow tired of it.

The figure shows how selectivity works with NFC. Notice that any card you want to read must be within the 4 cm to 10 cm reading distance — the NFC signal isn’t strong enough to read all the other cards in the area.

NFC selectivity is based on the short distance communication it provides.

Showing intent

NFC requires some sort of intent or gesture, an action on your part, to use it (after you set your device up to use NFC). The act of tapping your phone to the point of sale (POS) system at the cash register is a kind of gesture. Tapping the phone brings it in close proximity (within the 4 to 10 cm range) with the tag or other NFC-enabled device with which you want to interact. Unless you show specific intent to use NFC, by bringing an NFC-enabled device into close enough proximity with an NFC tag or other NFC-enabled device, NFC remains in sleep mode and you don’t have any connectivity.

You may see tapping referred to in other terms, such as bumping, beaming, touching, or waving. None of these terms adequately describes the gesture you must perform because of the real physical contact that is necessary to create an NFC connection. In order to work, the NFC-enabled objects must be close enough to establish an RF connection (which is 4 cm for NFC). It takes only milliseconds to make the connection, but finding the actual interrogation zone or sweet spot (the precise location between the two objects that allows for NFC connectivity) can sometimes be tricky for someone using NFC for the first time.

Creating secure access

The need for close proximity is what makes NFC secure — NFC requires a deliberate gesture to initiate a transaction, therefore nondeliberate transactions are difficult to initiate. You can’t simply pass by someone’s smartphone and read all the data from it. In order to read specific kinds of data from another person’s smartphone, you have to be close enough to connect to it (which is too near for comfort).

This means that you don’t have to worry about some hacker coming along and simply stealing your data, as would be possible with other technologies that are more vulnerable.

It’s important to realize that you do need to be proactive with every computer technology, and NFC is no exception. For example, you want to ensure that your smartphone or other NFC-enabled device has good password protection, just in case someone tries to gain access to it. A determined hacker will always find a way to gain access to data, but you can make things difficult, and perhaps the hacker will go bother someone else. You can read more about the potential vulnerabilities of NFC.