Click here to close now.




















Welcome!

Related Topics: @ThingsExpo, Java IoT, Mobile IoT, Linux Containers, Agile Computing, @BigDataExpo

@ThingsExpo: Article

How iBeacons Work for Indoor Location Based Services

Technical Guide and Recommendations

My colleague Peter Rogers is long suffering and obviously in need of sunshine.  He sacrificed his weekend to answer questions I presented him last week on the subject of iBeacons and how they work. I want to thank Peter for the following:

There is a lot of excitement about Apple's new iBeacon technology but most people still don't realise what it is or how to use it.

iBeacon is actually used in two contexts:

  1. It is primarily a Bluetooth Low Energy (BLE) Profile that enables a device to broadcast its relative position
  2. It is any hardware device that uses the iBeacon BLE Profile

The following paragraph illustrates this terminology effectively. A third-party beacon can use the iBeacon BLE profile to advertise its relative location and therefore be classed itself as an iBeacon. An iPhone can also use the iBeacon BLE profile itself to act as a Virtual iBeacon. In this case the power levels are generally higher and so you may get a more accurate result. There is nothing to stop an Android 4.3 device being able to use the iBeacon BLE profile to advertise itself as a Virtual iBeacon too. In fact any device that supports BLE can communicate using the iBeacon BLE Profile. The core difference that iOS 7 offers is that is normalises the results from the iBeacon (in order to avoid fluctuations) and it offers the new iOS 7 CLBeacon class within the CoreLocation framework.

Here are some interesting fun facts:

  • Apple does not produce iBeacon hardware
  • iBeacon is not the only BLE profile for beacons, there are others that predated it (S-beacon, Gimbal, GeLo)
  • Most beacons allow over the air (OTA) software updates which can be used to load the iBeacon profile
  • The beacons from different vendors often behave quite differently
  • iBeacons CANNOT reliably be used to pinpoint a precise indoor position - more on that later

The iBeacon BLE Profile does not have any payload. Instead it just sends three pieces of information:

  1. UUID - beacon manufacturer's unique identifier
  2. Major - a value that can identify a group of beacons (can be used for general region)
  3. Minor - a value that can identify an individual  beacon with a group (can be used for a specific location within that region)

The CLBeacon class offers three different properties for determining the distance from the beacon:

  1. Accuracy - the accuracy of the proximity value allegedly in meters - in practice this doesn't map directly to meters in most cases
  2. Proximity - the vague definition of proximity - immediate, near, far and unknown
  3. RSSI - the received signal strength of the beacon in decibels

The CLBeaconRegion class enables notifications when the iPhone detects that the range of an iBeacon has changed and this can be used to launch your App even if it was not running. The class also enables the construction of a Virtual Beacon whereby the iPhone itself uses the iBeacon BLE Profile to behave like an iBeacon.

This means that we can detect proximity to an iBeacon quite easily by using the Proximity property. In practice this means using the CLBeaconRegion class to set up notifications when we get a proximity of "immediate" to certain strategically positions iBeacons. The accuracy of the beacons can be increased by more power and changing the frequency of updates (the default varies per vendor). Increasing these two parameters obviously decreases the battery life. The simplest option is to look for cases where ‘the device is close to a beacon and the accuracy confidence is high' which translates into immediate zone. If you were however to put your hand in front of the device and the iBeacon, this can provide enough interference to push it back to the ‘near zone' although neither the device or beacon has actually moved.

Immediate Zone (0-20 cm) (0-8")
When a device is held up close to a beacon
Accuracy confidence is high

Near Zone (20 cm - 2 m) (8"- 6.5')
Within a couple of meters to the beacon
Accuracy is fairly certain

Far Zone (2 - 70 m) (6.5 - 230')
More than a few meters away
Accuracy is low or the signal strength is weak
[https://community.estimote.com/hc/en-us/articles/201029223-RSSI-Range-Zones-and-Distance-Accuracy]

A simple strategy is to have a Cloud hosted data set that determines the positions of the beacons for an App to dynamically load and refer to. If you try and hardcode the iBeacon positions or have a non-updateable configuration file then you would have to go through the Apple App Store review process every time you want to physically add a new iBeacon. You could also host other information such as broadcast messages, regions and what the major and minor versions actually represent. It would certainly be interesting to have Location Data Stores that can describe multiple indoor positioning systems and that you can look up based on UUID, major and minor. That could be perceived as a security risk in certain situations though.

There are definite differences between the beacon vendors, and things you should be looking into are as follows:

  • Secure firmware update over the air
  • Cloud management platform
  • iBeacon profile support
  • Configurable properties: radio output power; RSSI; iBeacon advertising interval; UUID, major; and minor
  • Developer SDK with documentation

If you buy beacons without the iBeacon profile pre-installed and they are not firmware updateable over the air then you are limited to older profiles. Likewise if the UUID is not configurable and not communicated in the documentation then you are locked into the vendor SDK. If the iBeacon advertising interval is very slow by default and not configurable then your beacons will be less accurate. Finally not being able to configure the power and RSSI means the beacons cannot be configured to be more accurate. http://localz.co/blog/ibeacon-ble-hardware-commercial-comparison/

There are also differences in the accuracy of iBeacons and associated SDKs as followed:

  • Drop-out rate
  • Consistency of beacon results amongst the same vendor
  • Correct implementation of measured power (he value of measured RSSI at a distance of one meter)
  • Change in accuracy due to rotation
  • Beacon interference with each other (not something that should have an effect)

http://blog.shinetech.com/2014/02/17/the-beacon-experiments-low-energy-bluetooth-devices-in-action/

The challenge comes when you want to try and use triangulation with the RSSI or accuracy properties in order to find out a precise location rather than ‘immediate', ‘near' or ‘far'. Using the accuracy property is best summed up by the following statement in the iOS 7 API documentation, "Accuracy indicates the one sigma horizontal accuracy in meters. Use this property to differentiate between beacons with the same proximity value. Do not use it to identify a precise location for the beacon. Accuracy values may fluctuate due to RF interference. A negative value in this property signifies that the actual accuracy could not be determined."

The distance estimate provided by iOS is based on the ratio of the iBeacon signal strength (RSSI) over the calibrated transmitter power (txPower). The txPower is the known measured signal strength in RSSI at 1 meter away. iOS also normalises the values to negate the fluctuations.

"At first glance it would appear that accuracy does seem to resemble distance. However at 0.5 meters, the accuracy underestimated distance, and by 1.5 meters, accuracy was an overestimation of distance. I decided to extend the distance out to 8 meters to see if the accuracy continued increasing with distance, however over the course of 80 seconds the accuracy of the beacon only reported an accuracy of 3.87m - some 4.13 meters shy of 8 meters. This was less than convincing that accuracy was representing distance. In certain ranges with this beacon there does appear to be some correlation between accuracy and distance. I turned the power up to 100% (+4bBm) and measured the accuracy at the same varying distances. This time I was seeing a very close relationship between accuracy and distance between 1 and 5 meters, though it did start to slip at greater distances (however at 15 meters there were desks and computers obscuring the path, so perhaps this is expected)." http://blog.shinetech.com/2014/02/17/the-beacon-experiments-low-energy-bluetooth-devices-in-action/

One equation that sums up the way to calculate distance is as follows:
P(d)[dBm] = P(do)[dBm] - 10n log (d / d0) - Z

  • d             The distance we want to know
  • d0           A measure of distance for a known power output
  • n             The way the signal power degrades over distance
  • Z              The environmental effect (which is quite large).

http://www.codepilots.com/2014/03/ibeacons-accuracy/

To provide the algorithm for Android or to create your own custom version for iOS then you would need to do something like the following:

1.     Normalise the RSSI and txPower values

2.     Calibrate each IBeacon with the txPower value to allow accurate distance estimates.

3.     Measured a bunch of RSSI measurements at known distances, then do a best fit curve to match the data points

4.     Convert the best fit curve into an algorithm

protected static double calculateAccuracy(int txPower, double rssi) {
if (rssi == 0) {
return -1.0; // if we cannot determine accuracy, return -1.
}

double ratio = rssi*1.0/txPower;
if (ratio < 1.0) {
return Math.pow(ratio,10);
}
else {
double accuracy =  (0.89976)*Math.pow(ratio,7.7095) + 0.111;
return accuracy;
}
}
http://stackoverflow.com/questions/20416218/understanding-ibeacon-distancing/20434019#20434019

There are mainly five issues with the approach of triangulation for more accurate positioning:

1.     In non-controlled environments, where you can find metals, and other objects that affect the signal, the received signal strength of the beacons changes so often that it seems impossible to get an error range below 5 meters.

2.     Other devices using 2.4 GHz frequency might be interfering with the Beacons' signal.

3.     Depending on the way that the user is handling the receiver device, the readings can change a lot as well. If the user puts his/her hand over the bluetooth antenna, then the algorithm will have low signals as input, and thus the beacons will supposed to be very far from the device.

4.     The directionality of the beacons and the receiver affects the readings.

5.     The beacons and their SDKs all have a different effect on the accuracy of the results

http://stackoverflow.com/questions/20332856/triangulate-example-for-ibeacons

"Having completed these experiments, I've been able to conclude that achieving accurate distance measurements with a single beacon is potentially possible, provided you have the right beacon and the right brand. Out of eight beacons, I only found one that was consistently achieving accurate distances. Given that there is so much inconsistency between the beacons and there is no guarantee you will even receive a beacon in an order that does provide accurate results, it seems the only way to achieve accuracy is by using many beacons and averaging the results."
http://blog.shinetech.com/2014/02/17/the-beacon-experiments-low-energy-bluetooth-devices-in-action/

Recommendations

1.     Ceiling mounting of beacons reduces variance and the user blocking the path

2.     Signal transmission and reception are dependent on the orientation of both the transmitter and receiver

3.     Radio absorption by the user is significant in determining distance

4.     Other radio interference does not seem significant

5.     Clustering of beacons does not seem to have an impact

6.     The measured power does not decrease uniformly as we move away from the receiver, this is the biggest limiting factor in using this technology for accurate positioning

7.     Increasing the power to the beacons using the vendor SDK increases the relationship between accuracy and distance (on correctly configured beacons)

8.     One mooted solution is to try to set up a beacon every X meters (X being the maximum error tolerated in the system) so we can track on this beacons grid the position of a given device by calculating which beacon on the grid is the closest to the device and assuming that the device is on the same position

9.     Choose the beacon vendor carefully based on online reports because functionality does vary a lot

10. Use lots of beacons and take an average due to drop out rates and inconsistency amongst beacons in the same place

I leave you some other reading material and the general advice that using relative proximity is probably a far lot simpler than trying to implement precise location. That means designing your solution architecture and physical deployment appropriately. I can see the ability to track a user through a shopping centre of airport, but the ability to pinpoint out a product in a retail store will be challenging unless beacons with very high power levels are used and ceiling mounted.

Additional Resources:

************************************************************************

Kevin Benedict

Writer, Speaker, Editor

Senior Analyst, Digital Transformation, EBA, Center for the Future of Work Cognizant

View my profile on LinkedIn

Learn about mobile strategies at MobileEnterpriseStrategies.com

Follow me on Twitter @krbenedict

Browse the Mobile Solution Directory

Join the Linkedin Group Strategic Enterprise Mobility

Join the Google+ Community Mobile Enterprise Strategies

Recommended Strategy Book Code Halos

Recommended iPad App Code Halos for iPads

 

***Full Disclosure: These are my personal opinions. No company is silly enough to claim them. I am a mobility and digital transformation analyst, consultant and writer. I work with and have worked with many of the companies mentioned in my articles.

More Stories By Kevin Benedict

Kevin Benedict is the Senior Analyst for Digital Transformation at Cognizant, a writer, speaker and SAP Mentor Alumnus. Follow him on Twitter @krbenedict. He is a popular speaker around the world on the topic of digital transformation and enterprise mobility. He maintains a busy schedule researching, writing and speaking at events in North America, Asia and Europe. He has over 25 years of experience working in the enterprise IT solutions industry.

Latest Stories
Any Ops team trying to support a company in today’s cloud-connected world knows that a new way of thinking is required – one just as dramatic than the shift from Ops to DevOps. The diversity of modern operations requires teams to focus their impact on breadth vs. depth. In his session at DevOps Summit, Adam Serediuk, Director of Operations at xMatters, Inc., will discuss the strategic requirements of evolving from Ops to DevOps, and why modern Operations has begun leveraging the “NoOps” approa...
SYS-CON Events announced today that G2G3 will exhibit at SYS-CON's @DevOpsSummit Silicon Valley, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Based on a collective appreciation for user experience, design, and technology, G2G3 is uniquely qualified and motivated to redefine how organizations and people engage in an increasingly digital world.
While many app developers are comfortable building apps for the smartphone, there is a whole new world out there. In his session at @ThingsExpo, Narayan Sainaney, Co-founder and CTO of Mojio, will discuss how the business case for connected car apps is growing and, with open platform companies having already done the heavy lifting, there really is no barrier to entry.
As more intelligent IoT applications shift into gear, they’re merging into the ever-increasing traffic flow of the Internet. It won’t be long before we experience bottlenecks, as IoT traffic peaks during rush hours. Organizations that are unprepared will find themselves by the side of the road unable to cross back into the fast lane. As billions of new devices begin to communicate and exchange data – will your infrastructure be scalable enough to handle this new interconnected world?
SYS-CON Events announced today that Micron Technology, Inc., a global leader in advanced semiconductor systems, will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Micron’s broad portfolio of high-performance memory technologies – including DRAM, NAND and NOR Flash – is the basis for solid state drives, modules, multichip packages and other system solutions. Backed by more than 35 years of tech...
This Enterprise Strategy Group lab validation report of the NEC Express5800/R320 server with Intel® Xeon® processor presents the benefits of 99.999% uptime NEC fault-tolerant servers that lower overall virtualized server total cost of ownership. This report also includes survey data on the significant costs associated with system outages impacting enterprise and web applications. Click Here to Download Report Now!
SYS-CON Events announced today that Pythian, a global IT services company specializing in helping companies leverage disruptive technologies to optimize revenue-generating systems, has been named “Bronze Sponsor” of SYS-CON's 17th Cloud Expo, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Founded in 1997, Pythian is a global IT services company that helps companies compete by adopting disruptive technologies such as cloud, Big Data, advance...
SYS-CON Events announced today the Containers & Microservices Bootcamp, being held November 3-4, 2015, in conjunction with 17th Cloud Expo, @ThingsExpo, and @DevOpsSummit at the Santa Clara Convention Center in Santa Clara, CA. This is your chance to get started with the latest technology in the industry. Combined with real-world scenarios and use cases, the Containers and Microservices Bootcamp, led by Janakiram MSV, a Microsoft Regional Director, will include presentations as well as hands-on...
Cloud and datacenter migration innovator AppZero has joined the Microsoft Enterprise Cloud Alliance Program. AppZero is a fast, flexible way to move Windows Server applications from any source machine – physical or virtual – to any destination server, in any cloud or datacenter, using its patented container technology. AppZero’s container is also called a Virtual Application Appliance (VAA). To facilitate Microsoft Azure onboarding, AppZero has two purpose-built offerings: AppZero SP for Azure,...
Organizations from small to large are increasingly adopting cloud solutions to deliver essential business services at a much lower cost. According to cyber security experts, the frequency and severity of cyber-attacks are on the rise, causing alarm to businesses and customers across a variety of industries. To defend against exploits like these, a company must adopt a comprehensive security defense strategy that is designed for their business. In 2015, organizations such as United Airlines, Sony...
SYS-CON Events announced today that HPM Networks will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. For 20 years, HPM Networks has been integrating technology solutions that solve complex business challenges. HPM Networks has designed solutions for both SMB and enterprise customers throughout the San Francisco Bay Area.
Consumer IoT applications provide data about the user that just doesn’t exist in traditional PC or mobile web applications. This rich data, or “context,” enables the highly personalized consumer experiences that characterize many consumer IoT apps. This same data is also providing brands with unprecedented insight into how their connected products are being used, while, at the same time, powering highly targeted engagement and marketing opportunities. In his session at @ThingsExpo, Nathan Trel...
Red Hat is investing in Tesora, the number one contributor to OpenStack Trove Database as a Service (DBaaS) also ranked among the top 20 companies contributing to OpenStack overall. Tesora, the company bringing OpenStack Trove Database as a Service (DBaaS) to the enterprise, has announced that Red Hat and others have invested in the company as a part of Tesora's latest funding round. The funding agreement expands on the ongoing collaboration between Tesora and Red Hat, which dates back to Febr...
IBM’s Blue Box Cloud, powered by OpenStack, is now available in any of IBM’s globally integrated cloud data centers running SoftLayer infrastructure. Less than 90 days after its acquisition of Blue Box, IBM has integrated its Blue Box Cloud Dedicated private-cloud-as-a-service into its broader portfolio of OpenStack® based solutions. The announcement, made today at the OpenStack Silicon Valley event, further highlights IBM’s continued support to deliver OpenStack solutions across all cloud depl...
Everyone talks about continuous integration and continuous delivery but those are just two ends of the pipeline. In the middle of DevOps is continuous testing (CT), and many organizations are struggling to implement continuous testing effectively. After all, without continuous testing there is no delivery. And Lab-As-A-Service (LaaS) enhances the CT with dynamic on-demand self-serve test topologies. CT together with LAAS make a powerful combination that perfectly serves complex software developm...