Beam & NFC

Beam & NFC
ab screenshot.jpg

Minus the slashing and sawing, smartphones are the Swiss-Army knives of connectivity. Thanks to their WiFi and Bluetooth capabilities, as well as a variety of ports and cables, you can zip files around all over to your heart's content. But setting up connections between two smartphones can be a Vulcan-like pain in the neck. If only there were a way to just "beam" data from one phone to another.

Scotty might not be able to solve that problem, but Google has by adding Beam to its Android OS. Beam is a capability built into Android-based smartphones, tablets and other mobile devices. It first appeared in the Ice Cream Sandwich version of the OS that debuted in October 2011.

According to Google representatives, you can sum up Beam as this: it's a feature that enables just about any type of proximity-based interaction.

Yes, that kind of corporate-speak is too vague for us, too. Here's another way of thinking about Beam. Just touch your smartphone to another smartphone or tablet to transfer files, Web site links, YouTube videos, links to apps, maps and directions - or just about anything else you can think of. Because Google's Android OS is found on about half of smartphones sold these days, Beam is already spreading throughout the land.

bumpandroid.jpg

Beam is a lot like having a Star Trek transporter device for your phone, and it relies entirely on NFC. Like Bluetooth, near field communication is a type of wireless communications standard. As its name implies, it works only in close proximity (about 10 cm or fewer) to another NFC device. NFC is still an emerging technology, and even by 2014, it may still only be shipped in about 20 percent of the world's cell phones.

You can buy NFC phones right now, though. The list of phones currently supporting the technology is somewhat short, but you can bet that the list will expand rapidly in the near future.

In order for Beam to work, both smartphones involved in the interaction must contain NFC chips or tags. Once you find a friend who has an NFC phone, Beam is designed to be exceedingly easy to use. Let's say your phone is displaying directions to your favorite sushi restaurant, and your friend wants to meet you there later. You can instantly share those directions with Beam. Just touch your phone to your friend's, and a "Touch to Beam" prompt appears on your phone. Tap the screen and your map immediately appears on the other phone. Now your pal has no excuse for getting lost or being late.

The same process works for Web sites, online videos, pictures, contacts and a whole lot more. Perhaps best of all, because Beam is part of Android's open-source development philosophy, any third-party company can dream up their own creative or crazy uses for Beam.

But at present, Beam will sit idle in a dark corner of most Android phones, primarily because so few phones actually have the NFC chips that make Beam work. As NFC technologies progress, however, you can expect dozens of Beam-powered applications that would make even an engineering whiz like Scotty proud.


HOW NEAR FIELD COMMUNICATION WORKS
nfc2.jpg
At its most basic level, near field communication is a standard for very short-range radio transmission. How short are we talking about? A pair of NFC transmitters can communicate at a maximum of just a few centimeters. Some chips are designed so that the only way they send and receive information is if you've touched the device you're carrying with the one with which you're going to communicate.
There are three modes of operation for NFC. The read/write mode allows an NFC device to read a tag like the kind you'd find in a poster. The peer-to-peer mode makes it possible for two NFC-enabled devices to exchange information. This lets you do things like tap your phone to another person's phone to exchange contact information. Finally, there's the card emulation mode. This is what lets NFC emulate (or imitate) a smart card like the kind you use in public transportation or ticketing systems.

What exactly happens when you tap two NFC-enabled devices together? It's easier to understand with a concrete example, so let's assume you're walking down the street when you see a poster for an upcoming performance by Man or Astro-man? Because you dig surf rock, you want to check it out. You also see some text on the poster that says it has an NFC tag.

You quickly whip out your smartphone and activate an NFC-reading app. Activating the app sends a signal to the NFC chip inside your phone. Electricity flows through the circuitry of the chip, generating a weak magnetic field. This means your smartphone is an active NFC device - it's using power to generate a magnetic field. You hold your phone up to the appropriate spot on the poster.

At this point, the weak magnetic field generated by your phone induces a magnetic field in the NFC tag within the poster. The magnetic field induces electricity in the NFC tag, which doesn't have its own power supply - it's a passive NFC tag. This creates a radio field. The radio field generated by the tag interacts with the field generated by your phone. The NFC chip in your phone detects and decodes the radio field. The information turns out to be a link to a video of the band playing live. The app gives you the option of visiting the link directly if you wish.


Tag_dispatching.png

Some NFC transactions will involve two powered devices. You may want to exchange some contact information from your phone with another person's phone. In an exchange, both devices act as active and passive components - when active, a device sends information and when passive, it accepts information. It takes just a moment for the two phones to send information to each other. Before you know it, your contact information is in the other person's phone and vice versa.

An active NFC device can only communicate with one target device at a time - you can't broadcast a message to multiple devices over NFC. The active device will send information to the target and will only accept a response from that target. Other NFC devices will ignore the communication.

It's important to remember that NFC just covers the actual transmission technology. It doesn't determine the content of those transmissions. The various hardware and apps that incorporate NFC chips will dictate what information changes digital hands. While the transmission technology is standardized, the content that can move across it isn't.

Because NFC is a standard, it has particular specifications. The transmission frequency for data across NFC is 13.56 megahertz. Like all radio signals, these travel in waves, with peaks and troughs. The distance from the peak of one wave to the next is a wavelength. At 13.56 megahertz, that means the signal moves 13.56 million wavelengths in the span of a second.

Currently, an NFC device can send data at a rate of 106, 212 or 424 kilobits per second. These speeds are fine for short bursts of information, but aren't suitable for heavy-duty tasks like watching videos or playing games.

credits: Jonathan Strickland, Nathan Chandler
edited by arawn
Nov 16, 2012