Location is everything

Before the hype surrounding RFID (radio frequency identification) gets out of hand, keep in mind that this isn’t the wireless solution for everything. RFID is an identification technology, not a tracking technology.

An RFID tag can tell you whether a pallet of widgets is in or out the dock door, on or off the shelf. But if you want to know where a palette is inside a million-square-foot warehouse, or locate people or high-value assets to within a few feet, you might want to consider a more cost-effective alternative.

RFID readers have a range of 10 feet, assuming the tags are oriented correctly. (If the tags, often manually applied to pallets, are oriented incorrectly or in the wrong place, readers won’t be able to pick them up.) Tags may cost as little as 23 cents each in volume, but the readers range from $800 for a PC card device to about $6,000 for a top-of-the-line model. And remember, each reader needs to connect to the Ethernet network; that means wiring drops and Ethernet switches in the warehouse ceiling. Although you can associate a tagged palette with the last reader that scanned it, the cost of deploying enough readers in a warehouse to know where the palette is all the time can be prohibitive.

And here’s an interesting conundrum: The more RFID range improves, the less likely you are to know where an item is, simply because RFID tags are passive. They can only be located by associating them with the reader that read them. At a 10-foot range, you know the item is within those 10 feet. At 150 feet, send out a search party.

One alternative is RTLS (real-time location system), also known as Active RFID. RTLS tags cost about $55 each and have a range of approximately 350 feet. An RTLS reader costs about $3,000.

Slightly more expensive at $100 apiece, Wi-Fi tags have a range of about 150 feet. But the cost of the “reader” can’t be beat; it seems like vendors are practically giving away Wi-Fi access points. What’s more, many companies already have a Wi-Fi infrastructure in place.

Wi-Fi tag vendor Ekahau sells location software called Ekahau Positioning Engine, which uses what’s called contour mapping. The system can locate individual Wi-Fi tags with an accuracy of 3 feet to 5 feet, according to Ekahau Vice President Tuomo Rutanen — even while the tags are in motion.

If you already have a Wi-Fi infrastructure, then the Ekahau model makes more sense than RFID for keeping track of pallets or certain high-value assets (rather than tracking everything that moves in that big old warehouse).

The Ekahau model may also form the basis of future E911 (Enhanced 911) requirements. In February, FCC Commissioner Michael Powell called on VoIP (voice over IP) vendors to create a system for wired VoIP phones to offer up location information. But what about VoIP wireless phones?

Rutanen points out that as students on university campuses and security personnel on corporate campuses adopt wireless VoIP, pinpointing the origins of emergency calls made on these devices will be no less important than it is for calls made on cell phones.

RFID is not going away, however — not with all of the major retailers and the Department of Defense making it a must-have. It will remain an important tool in our arsenal. In fact, in the future, IT’s biggest task may be learning how to best integrate the various wireless technologies.