A Bundle of iBeacons

Hamsa Mani
Thomas Jefferson High School for Science and Technology

Imagine a high schooler wandering the halls of the school building, completely lost, not at all knowing where to go for their meeting that started five minutes ago. Or the bake sale that will take place during lunch. Or the Prom asking scheduled to occur the next day. To tackle this issue, a mobile app was developed that displays a dynamic schedule of events – it changes based on your location in the building. But how practical is this idea?

The possibility to create an indoor navigational system, one like the Global Positioning System (GPS), has always been intriguing. Indoor Positioning Systems (IPS) have been studied for quite a few years, although they haven’t become as common as one would have expected. There are quite a few ways to pinpoint a mobile device indoors, the most prominent of which being the use of Bluetooth communication. Using Bluetooth Low Energy (BLE) signals in an IPS is a relatively new concept, and hasn’t been explored as in depth as IPS using Wi-Fi [4]. However, because most mobile devices these days have Bluetooth capability, the concept is becoming increasingly appealing. In his research, Puri developed an application that implemented the Bluetooth Application Programming Interface (API), allowing the phone to communicate with pre-existing Bluetooth modems in various rooms. But this method of Indoor Positioning is not very efficient. To improve this, several companies have begun marketing small devices called Beacons that can establish connections with mobile devices using BLE. One such device is Apple’s iBeacon, a colorful, aesthetic apparatus that can be attached to just about anything. Compared to other techniques, such as Wi-Fi or Radio-Frequency, the use of iBeacons is the most economical and accurate option [5]. Once I found a few packages of iBeacons in the lab, there was no question what IPS technique would be utilized.

First introduced in 2013, iBeacons use BLE signals to send their unique ID to a mobile device, which will then take some action, depending on what the developer programs it to do [5]. In a typical iBeacon-powered IPS, multiple iBeacons (in various locations) will be sending their own ID to the mobile device, allowing the relevant app to filter the IDs and produce a location. Yang et. al used iBeacons to create an IPS in a hospital, aiming to help nurses and doctors find their way around and respond to emergencies more efficiently. The application finds the user’s location and subsequently alerts them of the department in which they are currently in, and a list of rooms that need attendance in order of proximity and severity. While it is not known whether the app was ever marketed or sold to hospitals, this use case demonstrates that the use of iBeacons can help many people, and could even save lives!

In the last year or so, there have been many news articles discussing the uses and impact of iBeacons. For example, in a Washington Post article titled “How iBeacons could change the world forever”, Matt McFarland explores quite a few implementations of this Bluetooth technology. From having your front door unlock when you get close enough to scoring deals or prizes when you visit a car dealership or gas station, McFarland demonstrates that with the use of iBeacons, the possibilities are endless. However, McFarland mentions that “marketers will have to prove that less privacy is worth the payoff”, since customers would have to share their location or download that company’s application [3]. As one might expect, with every tech development, there comes a trade-off.

Apart from the lack of privacy, researchers have found other issues or flaws with iBeacons. Scientists from NIIT Technologies in Bangalore, India conducted a few tests to determine the reliability and accuracy of iBeacons [2]. After positioning three iBeacons, the researchers obtained the iBeacons’ RSSI (Received Signal Strength Indication) readings at various times, getting a good idea as to how strong the devices could communicate. To pinpoint the user’s exact coordinates within the room, the team used a method called Triangulation, the same concept that GPS uses. Akshay Tiwary, from the University of Waterloo in Canada, remarks that iBeacons reduce the scale of triangulation down to indoor levels, thereby reducing the error margin from 25m (that of GPS) to a smaller scale (A. Tiwary, personal communication, January 22, 2017). From the analysis of the RSSI readings, the researchers found that iBeacons emit less reliable signals if there are pillars in the way, or if the user’s device is pointing away from the iBeacon. Because of these limits, they concluded that iBeacons should be used in cases of proximity rather than position [2]. Taking this conclusion into consideration, three iBeacons were positioned around the Curie Commons, the central area of the Research Wing, and an Android application was programmed to reach out and capture the RSSI values of the nearest iBeacon. A database created prior to the test was then searched using the values received to identify the Commons area associated with the iBeacon. Accordingly, the user’s general location can now be related to the values received. But how can the user’s specific location be acquired?

Another group of researchers, part of Samsung Electronics in Korea and China, devised a technique that reduces the errors associated with using Beacons. Cho, Chen, Park and Lee created a self-correcting IPS consisting of a Target Beacon (an Apple iBeacon), a self-correcting Beacon, and a Measuring Device. To obtain the phone’s distance from the iBeacon, the self-correcting Beacon gets a signal from the iBeacon and broadcasts the RSSI. The measuring device then uses this reading and uses the power of the two Beacons to provide a much more accurate distance [1]. Due to the success of this test, it seems that the future of Indoor Positioning stems from the use of self-correcting Beacons.

Using the contextually aware app, a high schooler could walk upstairs and into the Curie Commons and feel a buzz against their hip. Pulling their phone out, they would notice a new notification after the IPS recognizes their position. Tap it open and a list of events would be displayed on the app’s home screen, generated by the nearby iBeacons, providing relevant information about nearby events.

References

[1] Cho, H., Ji, J., Chen, Z., Park, H., & Lee, W. (2015). Measuring a distance between things with improved accuracy. Procedia Computer Science, 52, 1083-1088. http://dx.doi.org/10.1016/j.procs.2015.05.119

[2] Deepesh, P. C., Rath, R., Tiwary, A., Rao, V. N., & Kanakalata, N. (2016). Experience with using iBeacons for indoor positioning. Proceedings of the 9th India Software Engineering Conference, pp. 184-189. http://dx.doi.org/10.1145/2856636.2856654

[3] McFarland, M. (2014, January 7). How iBeacons could change the world forever.

[4] Puri, S. (2015). Indoor positioning system using bluetooth. International Journal of Engineering Research, 4(5), 244-247. http://dx.doi.org/10.17950/ijer/v4s5/507

[5] Yang, J., Wang, Z., & Zhang, X. (2015). An iBeacon-based indoor positioning system for hospitals. International Journal of Smart Home, 9(7), 161-168. http://dx.doi.org/10.14257/ijsh.2015.9.7.16