Rolling Review Kickoff: Wi-Fi Location

Wi-Fi location is the ultimate answer to the needle-in-a-haystack problem: Your WLAN can enable asset tracking of expensive equipment, monitor locations of patients or personnel, facilitate stock replenishment, even pinpoint a single container within a huge warehouse. It can also tighten security by extending your NAC installation to tailor access based on a user's location within your facility. Talk about wringing additional value out of a major investment.

Wi-Fi location services have similarities to GPS and RFID technologies, but have thus far lagged in popularity. In 2006, just 135,000 Wi-Fi location tags shipped, according to a May 2007 In-Stat report. Why? They're expensive, and at an average of $60 a pop, no one is tossing Wi-Fi tags on $200 smartphones. In addition, battery life can be an issue. However, that report goes on to predict a 100% per-year growth rate, as vendors refine their offerings and prices drop. We see an opportunity for forward-thinking IT groups to get in on the ground floor with a technology that can pay off big in security and competitive advantage.

Right now, only a handful of vendors play in the Wi-Fi location space, but big names are represented, including Cisco, Meru Networks, Motorola, Newbury Networks and Trapeze. Top Wi-Fi tag vendors include AeroScout; PanGo Networks, which recently merged with InnerWireless; Ekahau; and WhereNet. Many of these provide applications as well, often focused on verticals, usually healthcare and logistics/cargo handling. Find our sneak peek at the vendor landscape and a discussion of use cases at Sneak Peek: Wi-Fi Location Services Vendors.

Enterprises considering Wi-Fi location services must ensure tight enough accuracy while minimizing expensive integration and customization. Currently, some amount of consulting is going to be required—Yankee Group suggests that professional services make up 20% of the cost of a location system.

To help you choose vendors that meet your needs while minimizing this expense, we're taking this Rolling Review in a new direction, issuing an RFI to a wide variety of vendors.

The Cafeteria Conundrum

We're seeing two main use cases for Wi-Fi location services: asset tracking and location-based control, where someone's in-building location determines network access. It's the first that garners the most attention, but that's changing as security-conscious companies realize that location applications go beyond traditional e911 applications, becoming a natural progression of NAC initiatives.

Think about it: The primary focus of network access control has been on who a person is, neglecting the where. No one wants even authorized users accessing sensitive data in public areas. Adding location capabilities to your WLAN can solve this problem because any Wi-Fi-equipped laptop can be tracked, no tags needed. Meru Networks and Motorola currently offer capabilities that enable organizations to limit access to the network and applications based on a wireless user's physical location. In addition, the wireless IDS/IPS market has begun to develop an element of rogue client or AP detection control based on location, work pioneered by Newbury Networks.

Most people are familiar with Wi-Fi location's kin, GPS and RFID. The satellite-based global positioning system technology is designed for outdoor use, while radio frequency identification is most often associated with the wireless version of retail barcodes. In fact, the term "active RFID" is often equated with Wi-Fi location services. But there are some important nuances: Passive RFID systems require close-proximity RF energy to excite the tags and cause them to transmit their IDs. Think Wal-Mart's well-publicized program where inexpensive ($1 or less) RFID tags are attached to cartons for warehouse processing. Readers operate at distances measured in inches or feet and in lower UHF frequencies, such as 433 MHz and 900 MHz.

Active RFID systems, in contrast, communicate via 802.11 or ISO 24730-compliant tags. Wi-Fi tags actively communicate with APs at 2.4 GHz, which has better propagation than 5 GHz. ISO 24730 tags also operate at 2.4 GHz but require readers that support the standard. Both are priced in the $60 range for small quantities.

Beyond Whiz Bang

While obtaining raw x/y/z coordinates is a neat trick, the vast majority of Wi-Fi location implementations involve creation of a new application or integration into an existing one. It's simply not enough for a product to spit out coordinates: A nurse looking for a heart monitor needs an exact floor and room number. A shipping yard wants to query by number or customer name and see all relevant waybill information and a map of where a container is in the yard. A key focus of our evaluation will be seeing how well vendors and VARs are producing apps to meet these needs.

Location-based security systems—that is, those that restrict access to the network or specific network resources based on location—don't require end-user interaction, but they do need to tie into enterprise directory systems so policies can be driven from existing groups and users.

Considering the topic is location, accuracy is a key concern as well. We'll go into much more depth in our upcoming reviews, but in a nutshell, you need to balance your application requirements with what your preferred vendors can provide against what's technically possible given your facility and WLAN. A business looking to keep track of computers may not need room-level granularity, just assurance that devices are still in the building, but a specialized instrument that's required on a moment's notice needs to be narrowed down to a single room.

Most Wi-Fi-based real-time location services offer accuracy in the range of six to 10 feet, but only some of the time; precision depends on AP placement and density, antennas, and the training that was performed to "teach" the system the location's RF environment. Newbury Networks claims accuracy within a 10-meter radius 99 percent of the time, which translates to getting it right within a circle covering 3,400 square feet. It can hit a three-meter radius 95% of the time, or 300 square feet. That's not very impressive—ISO 24730 products and low-frequency passive RFID readers all beat those numbers cold.

A WLAN designed for basic coverage will not perform as well as one dense enough to support Vo-Fi. If your application requires tight accuracy but your WLAN has areas of weak signal propagation, proceed with caution and insist on real-world pilots.

The other half of the equation is seek time, or how long it takes to converge on the location of the object. Cisco didn't have numbers to share at press time, but Newbury says its average is 30 seconds, while the fastest seek time is 10 seconds. In a competitive matrix it provided, Newbury claims that Cisco's results are 5 minutes and 1 minute, respectively. In contrast, Meru Networks demonstrated at Interop 2007 Las Vegas its location tracking product, in which a map displayed the movement of objects in real time. Meru told us its High Fidelity Location Manager works in real time to collect RSSI data across all managed APs and all controllers. After an initialization period, the product goes into a polling phase, collecting data as frequently as every 10 seconds so that tracking results appear almost instantaneous.

Still Reading?

Beyond challenges relating to application integration and accuracy, Wi-Fi location tags tend to have short battery lives because they need to send some kind of beacon or communicate with APs on a regular basis. What counts is how you define "regular."

If the tag phones home every few seconds, its battery life might be measured in hours or days. Reducing that to a few times per hour could increase battery life to months. Of course, if you're tracking laptops, Vo-Fi phones or other devices that are regularly recharged by end users, this is not a problem. If you're tracking a Vo-Fi phone or laptop, the APs are just using the device's Wi-Fi to home in on it. Some vendors provide an agent for laptops that assist in the process, but more often than not it's unnecessary. Wi-Fi tags sell for $50 to $60 dollars, compared with passive RFID tags that can sell for $10 to as little as 10 cents for high-volume retail environments. Clearly, tracking of objects will be limited to those items that are valuable enough to justify this cost. While an active technology will likely never reach the low cost of its passive brethren, we expect that as volumes rise and more tag vendors get into the game, prices will drop.

Finally, while location vendors claim adherence to standards to enable integration, what they really mean is that they use standard methods, such as SOAP/XML, to communicate proprietary information. The only two significant real-time location services API standards are ISO/IEC 24730-1:2006, which is more or less married to the hardware side—24730-2—and not Wi-Fi compatible and ALE, or application level events. Neither has a necessarily Wi-Fi -centric component.

We'll discuss all these factors and more in our ongoing analysis of RFI responses and evaluation. What we don't want is to discourage you—while there are still challenges to location services, vendors are working to overcome them. The rewards are too good to be left to verticals.

Sneak Peek: Wi-Fi Location Services Vendors

As we discuss in Wi-Fi Location: Let's Play Tag , we issued an RFI to nine Wi-Fi location services vendors. While we'll provide much more in-depth coverage in our upcoming reviews, here are our initial impressions based on early briefings. We also provide a rundown of the environments in which location services are making a difference today.

>> Cisco introduced its Wireless Location Appliance 2700 in 2005 and is now on the 2710 version. Cisco's dominant Wi-Fi infrastructure market share gives it a clear leg up when enterprises consider location. Although it supports PanGo, WhereNet and AeroScout tags, the company has been pushing forward a Cisco Compatible Extensions Wi-Fi Tag specification, encouraging Wi-Fi tag vendors to implement a common format that will enable Cisco infrastructure customers to select the tags of their choice.

>> Motorola through its acquisition of Symbol has been focusing on providing RF-agnostic location services. Rather than build a separate appliance, advance location services are provided as an add-on module to its RFS-7000 Wi-Fi controller. Motorola builds only the Wi-Fi and RFID connectors—partners will step in for GPS, cellular, and UWB (ultra wide band). By providing one connection point for all location services, Motorola customers can take advantage of "compounding" multiple technologies, such as Wi-Fi and passive RFID in hospitals, to improve robustness and accuracy and mitigate DoLA (denial of location accuracy) attacks. Motorola's deep resources, extensive partnerships and broad product portfolio make it a formidable competitor to Cisco.

>> Newbury Networks has had a focus on location technology from its beginnings, concentrating on the wireless IDS/IPS market with its Wi-Fi Watchdog product. Over the past 15 to 24 months, however, Newbury has gone whole hog, transforming itself into a "location systems company" and announcing last fall a location appliance based on its presence platform. Newbury's value proposition is that it supports heterogeneous wireless networks—a key point. Moreover, its layered architecture exposes APIs using standards-based access technologies, and the company provides "shrink-wrapped" location applications. Newbury lists PanGo as its only tag partners.

>> Trapeze Networks also has a location appliance, the LA-200, but it's not integrated into its controller; Newbury Networks and Trapeze list each other as partners on their Web pages. The appliance does integrate with Trapeze's management application, RingMaster, which provides a single administrative interface. This can be seen as Trapeze's move up the network stack in the same way Aruba has moved toward FMC (fixed-mobile convergence).

>> Meru Networks has taken a different angle than the three location appliance vendors, emphasizing NAC more than asset tracking. Meant as way to enhance security and enforce regulatory requirements, it offers a Windows-based application that ties into its infrastructure product and claims accuracy within 5 to 15 feet. It does have partnerships with AeroScout and Ekahau, but as with most of Meru's affiliations, integration appears limited.

Tag, You're It

>> AeroScout leads the market with Wi-Fi RFID tags, according to a recent report from In-Stat. Its tags can use either RSSI or TDOA (time different of arrival), a unique differentiator from competitors. Its tags can also operate in two modes: chirping, which is equivalent to sending short messages, and full association, which means tags maintain a continuous connection with the Wi-Fi network.

>> Ekahau focuses less on its tags and more on its software. Known extensively for its site planning and verification technology, the company leverages that expertise in its locationing platform. Tags are rechargeable, a necessary feature because they communicate actively with the wireless network. Rather than depend solely on the APs reading their signals, tags also read all AP's signals and communicate that info to their tracking console. This enhances accuracy at the expense of battery life.

>> PanGo was recently purchased by InnerWireless, a DAS (distributed antenna system) vendor. Its owner had a very strong share in the healthcare market and saw PanGo as a key way to provide a middleware piece for its existing Spot non-Wi-Fi real-time location services product. PanGo's software provides the necessary glue to tie location with applications.

>> WhereNet is easily the powerhouse leader in active RFID, but the non-Wi-Fi kind. Although it has included Cisco APs with its readers for quite some time, mainly for Wi-Fi client access, it only recently introduced a dual-mode tag, one that supports both ISO 24730 and Wi-Fi. The first works well in open spaces, and once the tags enter a traditional carpeted office, the existing Wi-Fi network can pick up where the other reader left off and continue tracking the item using Cisco's location appliance. WhereNet has strong market leadership in automotive manufacturing (Ford) and transportation with tags and specific vertical applications, totaling 175 operating installations. Support for Wi-Fi could open up other markets such as healthcare.

Use Cases

The retail segment has not found significant value in Wi-Fi location systems. Passive RFID, as embraced by behemoths such as Wal-Mart, is available at the low price points required for cost-sensitive retail operations and in the small form factors needed for packaging. This relegates Wi-Fi location systems to organizations willing to pay, not just for Wi-Fi location tags but for the expensive infrastructures needed to support them. The impetus is to track items, either because they're expensive, the coverage area is large, it's important to find them quickly—or IT just wants to know where their owners are.

In healthcare settings, where equipment costs are high and treatment specialized, many expensive instruments and devices are wheeled from room to room ... and sometimes that equipment rolls right out of the facility. By tagging devices and introducing "chokepoints" in the hospital, if a tracked piece of equipment leaves a pre-defined area, an alarm goes off so that security can chase it down.

A more mundane, albeit more generally applicable, use of location tracking is equipment maintenance. Whether the item needs to undergo scheduled service, re-calibration or repair, the equipment vendor or a contractor will be much more productive if he can go directly to the device.

Because tag costs are an important financial consideration in determining the ROI or benefits for a Wi-Fi location project, only heavy manufacturing can generally justify the expense. In automotive manufacturing, for example, containers carrying components and sometimes automobiles themselves are tagged. RFID vendor WhereNet shared examples within the aerospace and defense industries, where large items under repair, such as a satellite or radar arrays made up of valuable pieces, are spread out over a large area, but tagged to make sure they don't walk off as well as to assist personnel in locating them.

Large shipyards and cargo facilities handle goods in terms of containers, but thousands of them can litter the yard. Unless the staff maintains meticulous records, things aren't always where they're supposed to be, as containers arrive and leave and are shuffled about.

Passive RFID tags don't have the signal power to be detected over large areas, but a shipping container marked with an active RFID tag can be used in conjunction with electronic record-keeping systems to track a container as it's picked up, stacked or moved. And if it's relocated without having been properly recorded, the signal propagation characteristics of 2.4 GHz are good enough that it can be found. According to WhereNet, one of its customers went from having a poor reputation for losing items, to being one of the best handlers in a matter of a few months because of real-time location services.

For work sites with a keen sense of desktop security, there have been products on the market for some time that will lock a desktop when the user, who carries a wireless (non Wi-Fi) tag that communicates with a peripheral attached to the PC, steps away. When communication is lost, or the signal is weak, an agent on the desktop secures the system. While we have yet to see commercial applications that tie Wi-Fi-based real-time location services to desktop security, there's already something halfway there: Tracking a person's whereabouts. The most noninvasive example is the tracking of Wi-Fi clients, such as laptops or PDAs. A good example of this is MIT's iFIND feature, which allows students to share their locations with those on their buddy lists. The hospitality industry, specifically casinos, has recently begun giving VIPs RFID-enabled guest cards so that employees can quickly move in to assist big spenders as they enter and move about.