Wi-Fi-based real-time location systems (RTLSs), which use the 802.11 protocol to track connected devices, could be poised to grab some of the market generally associated with RFID tracking, allowing some enterprises to leverage their existing wireless networks to track devices, shipments, and even people.
The technology, similar in some respects to RFID tracking, has applications in both the shipment of Wi-Fi-equipped devices and the tracking of such devices, ranging from simple tags to laptops to expensive specialised equipment, while they are deployed for use.
"It makes sense for a lot of companies that have Wi-Fi, who aren't a green-field and who don't have RFID, to leverage existing infrastructure," said Stan Schatt, vice president and research director with ABI Research. He added that the medical equipment market was particularly well suited to growth in this area.
Although the sector earned just US$14 million in revenues in 2006, Wi-Fi RTLS is primed to explode to global revenues of US$800 million by 2012, a recent report by ABI forecast. Much of this revenue will go toward tracking devices, positioning servers, and providing installation services.
"A lot of healthcare equipment is starting to come with Wi-Fi radios already installed," Schatt said. "If it's not there, they add a Wi-Fi tag. It broadcasts and contacts the closest ... access points."
Such tags aren't too expensive and can last for months, emitting "chirps" to update any listening Wi-Fi access points about their current position and condition. But for buyers, Wi-Fi RTLS's key selling point is often its ability to avoid costly investments in new technology and hardware. Wi-Fi VoIP phones, laptops and PDAs -- even iPods and specialised industrial equipment -- can often be tracked out of the box by using any vendor's 802.11 access points (APs), which then provide the device with normal network connectivity while feeding geographical information and signal strength data to a central server that calculates where the device is currently located.
"As Wi-Fi gets further deployed, our solution gets further momentum in the marketplace," said Tuomo Rutanen, vice president of business development with Wi-Fi RTLS vendor Ekahau, which is represented in Australia by C1 Consulting. "Just the increase itself in terms of the use of Wi-Fi is fuelling our business quite considerably."
Device tracking can be a huge cost-saver, even aside from accounting for thefts or time wasted locating a device. According to Schatt, 15% of healthcare equipment is reordered because it's assumed to be lost, only to turn up later, leaving unneeded devices standing idly by.
The technology can also have applications throughout the lifetime of a device. A gurney with built-in monitoring functionality might go into "sleep mode" to save power before being transported to a shipping centre. While in sleep mode, the gurney "pings" occasionally, looking for APs with a pre-set ID and pass code. On arrival at the shipping centre, the gurney finds an AP and runs through some short diagnostic tests, checking to see whether any major damage has occurred in transit. As everything checks out OK, the gurney's location and status is noted in a central database that is checking order progress. Upon final arrival at the hospital, the gurney again reports its status and location, updating both the hospital and supplier that it has arrived undamaged.
While in the hospital, the gurney can give room-by-room information about its location, assuring hospital management that an appropriate number of gurneys are available by the emergency room entrance or to help locate a specific gurney tied to a patient in transit. This sort of real-time data does not come as naturally for RFID, which generally focuses on spotting devices as they funnel through a choke point, like a door or scanner. Generally, RFID also lacks much of the computing power necessary to perform diagnostic tests, although that capacity is now being built into some active RFID chips that have small processors built in.
"If you look at healthcare, where you've got things moving all the time -- doctors, nurses, crash carts, air pumps -- you need real-time visibility of where they are, and where they've been," said Chuck Conley, vice president of marketing at RTLS vendor Newbury Networks.
Although the technology is versatile, it has limitations. The location server must have data on each AP's position and signal strength, so it might not be able to pinpoint a laptop logging in at Starbucks. Also, to obtain relatively accurate positioning, there should be more overlap in wireless coverage, meaning that an additional investment - vendors estimated 10% to 25% -- in APs is often needed.
Once those APs are installed, however, the RTLS information needed is generally minimal, allowing the APs to act at almost full capacity in terms of bandwidth throughput.
So where can Wi-Fi-based RTLS make more sense than RFID?
The most important aspect to evaluate is what is being tracked. Standalone Wi-Fi tracking mechanisms have dropped in price and are likely to continue to do so, but they are not likely to go much below US$15 in the next few years. For an enterprise that is tracking machinery costing tens of thousands of dollars or devices that are already Wi-Fi enabled, this barrier is not much of an obstacle. In retail situations, however, an RFID tag, which typically sells for less than a quarter, makes more sense. RFID tagging also makes more sense outdoors, Schatt said, where Wi-Fi often encounters large amounts of interference. Wi-Fi tracking also tends to have a lower range of location accuracy.
Aside from medical markets, Rutanen said, the mining industry has shown a lot of interest in the technology as it deploys 802.11 to provide voice and data communications underground. These play to the technology's strengths, he said.
"The more complex [an] environment it is, the better it works, and the better accuracy we can provide," he said, pointing out that the denser cluster of APs with shorter ranges in these deployments allowed a more granular positioning view.
Newbury Networks has found success deploying RTLS for two very different types of applications. One focus has been museums, where the locations of devices like PDAs and audio players customise the types of content provided.
"As soon as I go over to the Napoleon exhibit, it gives me information on Napoleon," said Conley.
Another market Newbury has worked in is transportation. With many airports and train stations already providing wireless Internet access to patrons, laying on NTLS can give them a greater view of how security and other personnel are deployed. Conley said that Newbury sells trackable Wi-Fi devices that can be keyed to individuals for about US$50 and can go without a recharge for months at a time.
Using specialised software, location information can then be overlaid on a map to see where holes might exist in a security perimeter.