Welcome!

Agile Computing Authors: Yeshim Deniz, Rene Buest, Carmen Gonzalez, AppNeta Blog, Jyoti Bansal

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 an opinionated Senior Analyst at Cognizant's Center for the Future of Work, SAP Mentor Alumnus, speaker, writer, and mobile and digital strategies expert. He is a popular keynote speaker, and in the past three years he has shared his insights into mobile and digital strategies with companies in 17 different countries. He has over 30 years of experience working with enterprise applications, and he is a veteran mobile industry executive. He wrote the Forward to SAP Press' bestselling book on enterprise mobility titled Mobilizing Your Enterprise with SAP, and he has written over 3,000 articles.

@ThingsExpo Stories
The explosion of new web/cloud/IoT-based applications and the data they generate are transforming our world right before our eyes. In this rush to adopt these new technologies, organizations are often ignoring fundamental questions concerning who owns the data and failing to ask for permission to conduct invasive surveillance of their customers. Organizations that are not transparent about how their systems gather data telemetry without offering shared data ownership risk product rejection, regu...
WebRTC sits at the intersection between VoIP and the Web. As such, it poses some interesting challenges for those developing services on top of it, but also for those who need to test and monitor these services. In his session at WebRTC Summit, Tsahi Levent-Levi, co-founder of testRTC, reviewed the various challenges posed by WebRTC when it comes to testing and monitoring and on ways to overcome them.
Every successful software product evolves from an idea to an enterprise system. Notably, the same way is passed by the product owner's company. In his session at 20th Cloud Expo, Oleg Lola, CEO of MobiDev, will provide a generalized overview of the evolution of a software product, the product owner, the needs that arise at various stages of this process, and the value brought by a software development partner to the product owner as a response to these needs.
The Internet of Things can drive efficiency for airlines and airports. In their session at @ThingsExpo, Shyam Varan Nath, Principal Architect with GE, and Sudip Majumder, senior director of development at Oracle, discussed the technical details of the connected airline baggage and related social media solutions. These IoT applications will enhance travelers' journey experience and drive efficiency for the airlines and the airports.
In his keynote at @ThingsExpo, Chris Matthieu, Director of IoT Engineering at Citrix and co-founder and CTO of Octoblu, focused on building an IoT platform and company. He provided a behind-the-scenes look at Octoblu’s platform, business, and pivots along the way (including the Citrix acquisition of Octoblu).
In his session at @ThingsExpo, Sudarshan Krishnamurthi, a Senior Manager, Business Strategy, at Cisco Systems, will discuss how IT and operational technology (OT) work together, as opposed to being in separate siloes as once was traditional. Attendees will learn how to fully leverage the power of IoT in their organization by bringing the two sides together and bridging the communication gap. He will also look at what good leadership must entail in order to accomplish this, and how IT managers ca...
In his keynote at @ThingsExpo, Chris Matthieu, Director of IoT Engineering at Citrix and co-founder and CTO of Octoblu, focused on building an IoT platform and company. He provided a behind-the-scenes look at Octoblu’s platform, business, and pivots along the way (including the Citrix acquisition of Octoblu).
SYS-CON Events announced today that CA Technologies has been named “Platinum Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY, and the 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business – from apparel to energy – is being rewritten by software. From ...
DevOps is being widely accepted (if not fully adopted) as essential in enterprise IT. But as Enterprise DevOps gains maturity, expands scope, and increases velocity, the need for data-driven decisions across teams becomes more acute. DevOps teams in any modern business must wrangle the ‘digital exhaust’ from the delivery toolchain, "pervasive" and "cognitive" computing, APIs and services, mobile devices and applications, the Internet of Things, and now even blockchain. In this power panel at @...
SYS-CON Events announced today that Outlyer, a monitoring service for DevOps and operations teams, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Outlyer is a monitoring service for DevOps and Operations teams running Cloud, SaaS, Microservices and IoT deployments. Designed for today's dynamic environments that need beyond cloud-scale monitoring, we make monitoring effortless so you...
In his session at @ThingsExpo, Steve Wilkes, CTO and founder of Striim, will delve into four enterprise-scale, business-critical case studies where streaming analytics serves as the key to enabling real-time data integration and right-time insights in hybrid cloud, IoT, and fog computing environments. As part of this discussion, he will also present a demo based on its partnership with Fujitsu, highlighting their technologies in a healthcare IoT use-case. The demo showcases the tracking of pati...
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settle...
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, whic...
With 10 simultaneous tracks, keynotes, general sessions and targeted breakout classes, Cloud Expo and @ThingsExpo are two of the most important technology events of the year. Since its launch over eight years ago, Cloud Expo and @ThingsExpo have presented a rock star faculty as well as showcased hundreds of sponsors and exhibitors! In this blog post, I provide 7 tips on how, as part of our world-class faculty, you can deliver one of the most popular sessions at our events. But before reading the...
SYS-CON Events announced today that Cloud Academy will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Cloud Academy is the industry’s most innovative, vendor-neutral cloud technology training platform. Cloud Academy provides continuous learning solutions for individuals and enterprise teams for Amazon Web Services, Microsoft Azure, Google Cloud Platform, and the most popular cloud computing technologies. Ge...
The best way to leverage your Cloud Expo presence as a sponsor and exhibitor is to plan your news announcements around our events. The press covering Cloud Expo and @ThingsExpo will have access to these releases and will amplify your news announcements. More than two dozen Cloud companies either set deals at our shows or have announced their mergers and acquisitions at Cloud Expo. Product announcements during our show provide your company with the most reach through our targeted audiences.
TechTarget storage websites are the best online information resource for news, tips and expert advice for the storage, backup and disaster recovery markets. By creating abundant, high-quality editorial content across more than 140 highly targeted technology-specific websites, TechTarget attracts and nurtures communities of technology buyers researching their companies' information technology needs. By understanding these buyers' content consumption behaviors, TechTarget creates the purchase inte...
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy.
Your homes and cars can be automated and self-serviced. Why can't your storage? From simply asking questions to analyze and troubleshoot your infrastructure, to provisioning storage with snapshots, recovery and replication, your wildest sci-fi dream has come true. In his session at @DevOpsSummit at 20th Cloud Expo, Dan Florea, Director of Product Management at Tintri, will provide a ChatOps demo where you can talk to your storage and manage it from anywhere, through Slack and similar services ...
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo | @ThingsExpo, June 6-8, 2017, at the Javits Center in New York City, NY and October 31 - November 2, 2017, Santa Clara Convention Center, CA. Learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.