Ekahau Uses Cell Phones to Extend RTLS Beyond the Building

Apr 14, 2010Two U.S. companies are currently testing technology enabling them to employ smartphones as readers of Wi-Fi RFID tags. The phones capture the unique ID numbers transmitted by the tags, and forward that information via a cellular connection to a back-end server. The application, developed by Ekahau, a provider of real-time locating systems (RTLS), is intended to allow the businesses to track the locations and movements of tagged assets as they leave the vicinity of Wi-Fi nodes of wireless local area networks.

If the two piloted systems operate as hoped, the companies have told Ekahau they will then make decisions regarding whether to permanently deploy the solution to track assets on vehicles. Both firms have asked to remain unnamed.

The application, developed by Ekahau during the past year, was announced and displayed at the RFID Journal LIVE! 2011 conference and exhibition, being held this week in Orlando, Fla. The concept was inspired by an end user that had asked if smartphones could take the place of Wi-Fi nodes when tags leave a facility or other infrastructure, says Tuomo Rutanen, Ekahau's VP of business development. Using Wi-Fi-enabled Android and Apple iPhone handsets, Ekahau developed the solution that would require a customer that already had an Ekahau RTLS installed at its site, to attach tags—such as Ekahau's t301A asset tags—to items that would be taken to a location beyond the range of that site's Wi-Fi infrastructure; set mobile phones to "tether" mode (originally designed in cellular phones to allow laptop computers to utilize a Wi-Fi link to access the Internet via the phone's 3G or 4G connection); and store tag-read data on their existing Ekahau software. No additional software would be required on the phone itself, the company reports.

One of the two companies trialing the system is a health-care firm that intends to utilize such a system on ambulances to track the equipment taken on emergency calls. The company has attached an Ekahau tag to each piece of equipment. Because the Wi-Fi nodes installed within its facility, it can track the locations of tagged items as they are moved around the building. For tagged equipment placed in the ambulance, a mobile phone operating in tether mode would function as a Wi-Fi node.

Typically, Rutanen says, the phones can capture read data from the tags at a distance of 10 to 40 feet. In the health-care company's trial, the mobile phone is placed in the cab of the vehicle, along with the driver. Tags attached to items in the back of the ambulance would then transmit their unique ID numbers to the phone. Once the phone receives those IDs, it forwards that information to the back-end server via the cellular connection. Although the initial trial is intended only to simulate a real-world environment (the system is being tested in an ambulance-sized vehicle), the technology, once in full deployment, would allow a user to access the Ekahau software to determine in real time which assets are in the ambulance, as well as when they are removed, based on when particular tag IDs are no longer being read. That time of removal from the ambulance could then be correlated with the driver's route (that is, where he or she was expected to make stops), in order to determine where the item was removed, or the phone's GPS functionality could be used to pinpoint the asset's location.

During the second trial, a company that manages hazardous materials is testing the system's functionality by placing a smartphone in the cab of a delivery vehicle. While the pilot is initially testing the system by tracking tags placed in the rear of the vehicle, in the event of an actual deployment, the tags would be attached to containers of hazardous materials. The phone would send the ID numbers of all tags within its read range, and if it ceased detecting a specific ID, the Ekahau software would determine that the item had been removed from that vehicle, and could thus issue an alert or simply store that data.

The technology could also work with Ekahau's sensor tags, Rutanen notes, allowing users to monitor, for instance, if the temperature in the back of a truck rises above a specified threshold. That data could be captured in the back-end software via transmission from the driver's mobile phone.

According to Rutanen, the testing has been underway at both companies for approximately three months, and is slated to continue for about 45 more days. He envisions that the technology could also be employed by health-care companies to allow patients to communicate with a hospital or a physician via a two-way Ekahau badge attached to a lanyard worn around a person's neck. If a patient has an emergency, for example, he or she could pull the tag to trigger an alert that could be captured by the mobile phone and sent to the back-end Ekahau software, which would then send a message to an emergency medical technician (EMT) or other health-care worker. Moreover, he says, hospital staff members could send messages to that patient, such as "take your medication," by transmitting data to the mobile phone, which would then forward the message via a Wi-Fi connection to the tag, which would subsequently display that text on its screen. To date, Rutanen notes, such an application has yet to be tested.