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The Beacon Evolution: A Guide to Bluetooth Asset Tracking

Bluetooth beacons are part of the larger family of BLE devices. Some of Real-Time Location Systems use these for Bluetooth location tracking. The Bluetooth device regularly sends a brief message that can be picked up by a Bluetooth gateway, that way the gateway knows that it is, for example when worn by a person, is in the proximity of the location where the gateway is installed.

Bluetooth beacons are similar, in a way, to a barcode, except that it will send its identification number automatically, whereas a barcode needs to be scanned to know its number.

Here is a list of everything you need to build this hardware: a small radio transmitter, a battery, some low-cost electronic components, a Printed Circuit Board (PCB) and a (plastic) enclosure. Sometimes sensors are added to the mix. There are multiple manufacturers that make small radio transmitters that are compatible with the beacon format defined by the Bluetooth standard.

Such battery-powered devices can typically last for a year or even more.

How Do Bluetooth Beacons Work?

The Bluetooth beacon can transmit a short wireless message on a regular basis, for example at an interval of every second.

Bluetooth beacons operate differently from Bluetooth devices such as headphones, car kits and Bluetooth speakers. They are not to be first paired with another Bluetooth device and do not have to establish a connection with another Bluetooth device.

The beacons can simply send a message at any time, hoping another device will receive it, and then shut down. That allows their messages to be very short. As a result these devices can have a battery lifetime of a year, even on a small coin cell. They can save the battery even for multiple years by sending beacons more infrequently. For full clarity, this tech do not use two-way communication but rather one way communication. They consume much less power than regular Bluetooth communication does.

The beacons use Bluetooth as the fundamental wireless technology, but in a different way from typically Bluetooth applications such as headset and wireless speakers. They use the Bluetooth Low-Energy specification for communicating and a Bluetooth low-energy beacon is thus legitimately a Bluetooth device. Beacons, long-range and short range alike, will send a short message in this way.

There are apps for Android and iOS where the smartphone app can send out Bluetooth beacons and thus act as Bluetooth beacon hardware.

There is even more than one third-party application for Android and iOS that will receive Bluetooth beacons from BT hardware. The user will then use their mobile device as a Bluetooth gateway. The user with the help of the app can then receive all devices sent out in its proximity. Your smartphone battery will not be able to act as a true Bluetooth gateway though because of its limited battery capacity.

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What is The Difference Between WIREPAS and Bluetooth?

Bluetooth and WIREPAS are both wireless communication technologies. They are embedded in electronic hardware devices that perform a certain function (e.g. a temperature sensor) and transmit data wirelessly.

Bluetooth is better known than WIREPAS because Bluetooth is a consumer application technology, and thus well known to the general public, whereas this tech is intended for industrial applications where reliability, scalability and security are important qualities.

The secret sauce of this technology is that the devices are all time-synchronized with each other, this means that a device can schedule the transmission of a message when it knows the receiving device will be listening. WIREPAS has multiple significant advantages:

Devices can go to sleep when they know that no other devices will be sending it messages. That way the device can be 1000 times or more energy efficient than a device that always needs to be powered up to listen for incoming messages. That is the reason why Bluetooth gateways cannot work on batteries, as the batteries would be drained in a matter of days.
Devices can forward messages for other WIREPAS devices, such that a message can travel a much further distance than what a single wireless link can achieve, this is called a wireless mesh network. A mesh network can grow to tens of thousands of devices, spanning a vast area.
Under this tech any device can act as the receiver for any other device within wireless range. In a typical application a WIREPAS device can see 10 other devices within range. This means that there are multiple redundant paths to send a message across the network. This greatly increases the reliability of the system. In a Bluetooth network, the wireless device typically only has 1 or 2 Bluetooth gateways within wireless range, thus limiting the options and causing messages to be lost in case of interference or objects blocking the wireless link.
These devices are time-synchronized, they can stay silent when they know another WIREPAS device will send a message. That way message collisions, which make colliding messages unreadable, are eliminated. With Bluetooth beacons there is no such time-synchronization. So when they are put within each other’s wireless range, regular message collisions will occur, blocking all communication as soon as there a few 100 devices in the same environment.

Bluetooth, as well as WIREPAS, has gone through many iterations and it can be expected that they will further specialize in their own areas, consumer-oriented for Bluetooth and industrial-focused for this technology.

In summary, the most popular use of Bluetooth is in (low-cost) consumer applications. For WIREPAS the most popular use is in industrial applications, where reliability, a long battery life and scalability are important.

Note also that WIREPAS is fundamentally a two-way communication technology whereas Bluetooth beacons (but not other Bluetooth variants) are a one-way communication technology.

What Can a Bluetooth Beacon Be Used For?

The beacons will help you to track people after attaching the device to the person. In this case, they often comes in the form of an employee batch. Even a smartphone can act as a beacon, see below.

Beacons can also be used to track tools. For example you can use the beacon to track the location of a welding station. In this case, it is important that the number of tools in the same wireless environment is limited because they interfere with one another as soon as you are using multiple beacons in each other’s proximity and there are too many of them, see also later.

The beacon and the object it is attached to require Bluetooth gateways for indoor positioning with an accuracy of typically 5m to 8m. Beacons transmit data consisting of a unique serial number to identify it.

Apart from the serial number, and sometimes additional sensor data, such as for indicating that the temperature threshold has been breached, the frequency by which they send out a message will affect the battery life and the number of messages remaining in its lifetime. The transmit power, battery status, and transmit frequency are thus all related.

How Do BT Beacons Track Location?

The idea that BT beacons track location, although often heard in the asset tracking world, is not technically correct. Bluetooth beacons have no way to track their location. Bluetooth beacons work on the principle of sending out a short message on a regular basis, for example once every second. In a location where the devices need to be tracked Bluetooth gateways are installed, typically at a distance of 15m in both horizontal directions, and repeated on every floor. Bluetooth gateways then pick up the messages from them, acting as the receiving device.

Typically, the gateway that picks up the strongest message from the BT beacon is considered to be the approximate location of them. More sophisticated systems will combine received signal strength of a message by several gateways to calculate a somewhat more accurate location of the devices.

The advantage of using beacons for location tracking is that they are very cheap. The disadvantages are that:

Installing and running power wires to a large network of Bluetooth gateways is very expensive.
As soon as there are a few hundred beacons in the same environment, the system breaks down because the messages from the devices start colliding. This is comparable to people speaking at the same time and in the same room, causing a cacophony of noise. That is why BT is not useful to track location except for the simplest inventory management applications.

For Bluetooth beacons to be used in an indoor positioning system, or as tags in real-time location systems, the accuracy requirements cannot be more than 5m to 10m.

For more accurate asset tracking, ultra-wide band technology needs to be used instead of this devices.

How Are Bluetooth Devices Tracked?

Bluetooth tracking applications, also known as BLE location services, use Bluetooth beacons for indoor positioning. The Bluetooth devices are tracked using a network of Bluetooth gateways spread out across the facility where tracking is required. The Bluetooth device that is to be tracked sends out regular messages, called Bluetooth beacons. The message is received by a gateway. The Bluetooth device is then assumed to be in proximity of this gateway.

Sometimes the message is received by multiple neighboring gateways. The higher the signal strength indicator RSSI value (RSSI = received signal strength indication) as the Bluetooth beacon has been received by the gateway, the closer that the device is likely to be to that gateway. Using the received signal strength the distance between device and gateway can be estimated. The distances to the multiple gateways can be combined to estimate the location of the devices, typically with an accuracy of 5m to 10m. This works best when the transmission power and the receiver sensitivity of the gateways are known.

In conclusion, with BLE beacons and Bluetooth gateways a simple but crude tracking system can be built.

Are These Beacons for Asset Tracking Secure?

Bluetooth beacons for asset tracking are not generally secure. Anyone with a Bluetooth receiver (even a smartphone) can receive Bluetooth beacons easily.

How Many BLE Devices Can Be Connected?

BT beacons only send simple messages and cannot be actively connected to another device. BLE devices, however, where BLE stands for Bluetooth low-energy technology, can connect to a Bluetooth host, such as a computer or a smartphone. A host device typically supports multiple simultaneously connected BLE devices, for example up to 7. BLE devices, to the contrary, typically only support a single connection at any point in time, to one host.

Using Bluetooth low-energy devices the host device, such as a smartphone, peripheral devices such as a smartwatch can be connected with very low-power consumption.

Do Wireless Access Points Extend Bluetooth Range?

Wireless access points do not technically extend the Bluetooth range, at least not using Bluetooth for the (wireless) communication. Instead, wireless access points can receive Bluetooth beacons, and then repackage the data from this devices into a Wi-Fi or Ethernet (or other) message. In a way, the Wi-Fi or Ethernet acts as a relay Bluetooth beacon, although the relaying does not happen using Bluetooth.

How Much Does a Bluetooth Beacon Cost?

You can buy one of these pieces of technology for as low as a few dollars. More expensive Bluetooth beacons typically have sensors embedded, such as a temperature sensor. The low-cost point can be achieved because a Bluetooth beacon does not require a two-way communication capability and is simply a transmission-only, one way communication device. They can also operate on a low-cost small coin cell battery.

The downsides of the low-cost nature of Bluetooth beacons are described in other sections of this page

Do Bluetooth Beacons Work With Bluetooth Turned Off?

They do not work with the Bluetooth function turned off. However, Bluetooth beacons have the capability to turn themselves on for a very short time, send a short message, and then go back into a very low-power ‘sleep’ mode, almost (but not quite) like turning off.

This technique is known as power duty-cycling, where the device is in turns offline and online. The cycle can be repeated every hour, minute, second, or even multiple times per second. This way beacons can preserve battery capacity and still be discoverable in a relatively fast way.

The disadvantage is that these devices do not support two-way communication, and that they do not listen to other ones sending messages, thus leading to message collision and corruption when too many devices are at the same location.

What Are The Most Common Bluetooth Location Services?

As explained above the most common and the most important Bluetooth location services are consumer and retail applications and are much less suited for industrial applications, where reliability and scalability are paramount.

The most common Bluetooth location services are related to people tracking, for the simple reason that most people carry smartphones and that most smartphones send out Bluetooth signals. These Bluetooth signals can be discovered by nearby Bluetooth gateways.

The gateways can thus detect how many and which Bluetooth devices are nearby. Although these Bluetooth signals do not carry the identity of the person carrying the smartphone, the Bluetooth signals do provide a unique number for every device; thus individual smartphones can effectively be identified.

Here are some of the most common Bluetooth location services using this people-tracking capability:

Shopping center
Sports arena
Trade show
Tracking people in an office

Some companies are using beacons to implement industrial applications, but usually with little success for the reasons explained above.

Conclusion

At RedLore, we specialize in enterprise-grade RTLS solutions tailored to transform your asset tracking and indoor navigation. With extensive experience deploying innovative platforms across industries, RedLore has the expertise to unite devices, data and workflows in new ways. Our end-to-end approach covers assessment, planning, procurement, deployment, integration, and support – ensuring maximum ROI on your RTLS investment. Let RedLore’s team show you how real-time locating systems can streamline operations, boost productivity, and drive value for your organization.