"To my way of thinking, location-based tracking is essentially a default requirement in most enterprise-class WLAN systems," said Craig Mathias, principal of research firm Farpoint Group. "It's something you want in the system, whether or not you're using it. I think we're going to see increasing use of it. It will be broadly available within most wireless LAN product lines and through simple integration with third parties."
RTLS can enable basic location-based services that improve the way companies use common services such as faxing and printing, Mathias said.
"It can look at what printer you are nearest to, and what fax machine you are close to, and direct output to that printer or fax machine," he said.
Wi-Fi RTLS for location-based security and authentication
Some vendors are pushing out further, finding even more critical applications for RTLS, such as enhanced wireless LAN security.
Trapeze Networks recently introduced its RF Firewall, a location-based security technology driven by the RTLS technology it acquired last year with its purchase of Newbury Networks. The technology allows an enterprise to establish location-based security procedures and policies for accessing the wireless network. Using location algorithms developed by Newbury, the RF Firewall can determine the location of a wireless-enabled device and apply security policy to that device based on the location.
For instance, the technology can forbid devices to access a wireless network from an office parking lot.
"What they're basically doing is adding location as a variable in authentication," Mathias said. "If you're in the wrong location -- even though you have the right technology and you might be otherwise authorized -- you're not getting on [the network]. For example, an enterprise may want to disable any access from a parking lot outside. They may want to make sure guests only have access in certain parts of the building. Without location, you can't do these things."
Wi-Fi RTLS uses proliferate
More and more vendors are adding RTLS capabilities to their products or establishing partnerships with third-party software vendors like AeroScout and Ekahau, whose patented algorithms can determine the location of objects in a network based on the data it collects from wireless LAN infrastructure.
Cisco Systems introduced its own location-based technology several years ago with its 2700 Series wireless location appliances. Cisco replaced those appliances last year with its Mobility Services Engine (MSE), which has open APIs that allow third-party vendors to tie into location information and use it in their own applications.
"[The MSE] wasn't necessarily a new technology for Cisco, but it was an improvement in what it's been doing in pure Wi-Fi [RTLS]," said Chris Silva, analyst with Forrester Research. "They added the ability through tying into CCX (Cisco Certified Extensions) and certifying a lot of [third-party developers] out of the gate, to do more than just [device tracking] if you have an active RFID Aeroscout tag. Now it's all Wi-Fi-enabled mobile devices, presumably anything from an iPhone to things that don't use 802.11, like ZigBee."
For instance, at Interop this spring, NetScout, the top network management and performance vendor in the market, debuted integration of its Sniffer Global network analyzer product with Cisco's MSE. By tying into MSE, Sniffer can find the location of an endpoint device that is experiencing WLAN performance problems, determine which access point it is connecting through, and analyze the activity of other wireless devices in proximity to the endpoint device to determine the cause of the performance issue.
Capitalizing on Wi-Fi RTLS: Careful network planning
The application possibilities for WLAN RTLS are intriguing, Silva said, but he added that most enterprises aren't quite ready to get the most out of this technology.
"I have yet to see in most verticals an organization that has deployed access points to the level [required] for the granularity that this kind of system needs," he said. "It's sort of a great promise of tomorrow. If you're deploying access points in a building and you're deploying them in four corners of a floor so everyone gets one or two bars of coverage on their laptops, that's probably not going to give you the granularity for saying, 'I am in room A versus room B,' because that might be a difference of three feet."
Silva said RTLS for wireless LANs requires a great deal of network planning and site surveying in order to design a wireless network that can generate useful location information.
And yet the use cases are there in certain vertical markets, such as healthcare and manufacturing, to motivate some organizations to commit the man-hours and capital investments necessary to pull RTLS off.
"Healthcare is the poster child for Wi-Fi," Silva said. "Asset reclamation … wheelchairs are a huge issue in hospitals. They go missing, and they are very expensive."
Basic RFID technology can track when wheelchairs pass through certain locations, such as a hospital entrance, he said, but a wireless LAN with RTLS capabilities can be much more precise. "If a department is running low on wheelchairs, they do a scan on the Wi-Fi network, and you may see, because they are tagged with little Wi-Fi chips, that they're all congregated by the exit. You don't have to go out and buy new wheelchairs. You just need to make sure they are returned."
There are six or seven "interesting techniques" for determining real-time location information, Mathias said. These techniques all involve some combination of factors such as signal strength, time difference of signal arrival and time of signal flight.
"The real question is: How accurate is the technique?" he said. "There are a number of variables: How much does it cost? How easy is it to deploy? How easy is it to manage? What facilities are enabled and what applications? And finally, how accurate is it? And by accurate, do you mean absolute accuracy or accuracy over a given period of time? You'd be surprised how big an exercise it is [to evaluate RTLS]. Deploying this technology can take days. Then you have to test it and calibrate it. And then you need to decide on some sort of metrics for measuring performance."
Mathias offered up a three-step process for evaluating location-based wireless technologies.
- Write up a list of requirements: "What do you want to do? Is security an element? Is the tracking of key objects an element? Is tracking people an element?"
- Define your constraints: "How accurate do you want it to be? What will be the coverage area?"
- Construct an objective test: "But that's a daunting activity. It's harder to test location tracking systems than it is to test wireless LANs themselves. That's why a lot of enterprise-class wireless LAN vendors have incorporated location tracking into their product lines – so their customers don't have to think about it. They can just buy it. That's not to say the debate is settled, but that is a reasonable strategy."