When setting up RTLS (Real Time Location Services) you start to run into all kinds of jargon. What, exactly, are beacons, tags, and gateways? And what kind of technology should you use to communicate between them?
An loT depends on your specific use case, but here's some information you might find helpful.
A beacon is a small transmitter that is attached to an object and produces a signal. The beacon broadcasts a simple ID, that is then identified by a reader. The reader, which can be a smartphone, then pulls the related data from the cloud. The signal broadcast by the beacon includes its ID, firmware, battery level, and potentially other data. It does not include location data, which is determined by the signal strength at the receiver.
This allows, for example, for a museum's smartphone app to provide a visitor with information about an exhibit sent directly to their phone without them needing to stop and scan a QR code. Beacons can also be used for indoor navigation, triggering automated events (for example, when you walk into a trade show booth, it might start the video playing), and for security.
Fixed beacons are used because they don't track individuals, which is a privacy concern in most public areas. Users consent to receive beacon notifications when they download the app. They also have to turn Bluetooth on when using BLE beacons. (More on the tech differences later). The big difference between beacons and tags is that beacons are stationary, while tags move.
A tag is attached to an object or a person and tracks their location. In many cases, tags are attached to employee and visitor badges. They can also be attached to goods in a warehouse, vehicles such as forklifts, etc.
The tag also broadcasts a simple ID number which is then translated by software running in the Cloud. Tags are primarily used for two purposes: inventory control and employee tracking.
Some use cases combine both. For example, in modern hospitals, a tag on a nurse's badge registers her location, and a tag on a defibrillator, also showing location, allows the software to tell the nurse where the nearest functioning defibrillator is. This technology can literally save lives in busy hospitals. Tags can also be equipped with other functions, such as panic buttons to allow staff to summon help in an emergency or alerts if they detect abnormal environmental conditions. For example, if you have consumables or medicines that need to be kept below a certain temperature, a tag can give a warning if the temperature rises too high.
Same technology, different usage:
Tags = movable, Beacons = stationary
The data from tags or beacons has to be picked up somehow, and that is where gateways come in. Gateways are fixed devices that receive the location or telemetry data from tags and pass it on to the software.
The more gateways you have, the more expensive your system but also the more accurate. When designing a system, gateway locations are vital to get the right level of granularity and ensure there are no dead zones where location tracking ceases to function.
Again, beacons are generally used in cases where you do not want to track people. Tags are used in cases where you do. A museum does not need to know where visitors are, whilst a hospital does. So, which you use depends on your purposes.
Retail stores and other public facing industries generally use a beacon system coupled with a bespoke smartphone app. Warehouses generally use a tag and gateway system to track inventory and help employees do their jobs better.
So, now we understand beacons, tags, and gateways, how about the difference between BLE, Wi-Fi, RFID and UWB technology.
Let's start with the easy one.
In today's world, we all use Wi-Fi pretty much every day. You probably have a Wi-Fi network at home, you certainly have one in the office. Wi-fi allows for high bandwidth communication between devices, resulting in the ability to work on the deck with your laptop.
Wi-fi is also sometimes used for location-based services. It has two advantages: The first is that the building likely already has Wi-Fi infrastructure that can be used, and the second is the higher bandwidth. The longer range can also be useful.
However, because of that, Wi-Fi tags tend to be more expensive and have shorter battery life, two things which make them less feasible for applications that use a lot of tags.
Wi-Fi is generally not used for beacons because most people want to use the wi-fi function on their phones to connect to provided internet access. Wi-Fi access points are also costly and have questionable security. The accuracy tends to be a lot lower due to the cost of both beacons and tags, making it of little use in applications such as inventory tracking which require high accuracy.
RFID stands for Radio Frequency Identification. This is a technology that has been used for inventory control and health care purposes for some years now. It is commonly used to replace bar code based technology as it's slightly faster than the worker having to take the time to scan a code.
RFID tags may be active or passive. Active tags constantly send a signal, while passive ones respond to the presence of a reader. The advantage of passive tags is that because they don't have their own batteries, they last a lot longer. They are also cheaper and smaller, for the same reason. However, due to their limited range, they are not used in RLTS applications, but rather in tasks that involve short-range manual scanning, such as contactless payment.
The disadvantage of RFID is that it requires a special reader, rather than a standard device such as a phone. However, once a company has started using RFID it is best to continue, at least until the readers need to be replaced. Also, RFID broadcasts in all directions, avoiding the need for LOS. However, the signals are easily intercepted.
Because of its age, RFID has less functionality than newer systems, and because it requires expensive readers it is not useful for extensive visitor/employee tracking or for indoor wayfinding.
UWB stands for ultra-wideband. It's also a radio-based protocol. Because it operates as a very high frequency, it can be used as a way to image a space and can provide very precise location services. UWB works by sending out pulses across the frequency until it finds a receiver (a beacon) and then it locks on to the beacon and can send large amounts of data. One use case of this might be to allow large files to be wirelessly transferred between devices without the need for a receiver.
In real time location services, UWB is still very much an emerging protocol. The ability to transfer a lot of data might be useful in high security situations where accessing the cloud could be problematic, but is not useful for the majority of asset tracking applications. However, it does work only at line of sight, which might require more gateways. Also, Apple has patented the use of UWB with beacons, which is likely to increase costs. So far, only high end iPhones have UWB built in, which limits its use as a beacon technology. It does have the advantage of having even greater power efficiency than BLE, but it achieves this by transmitting much shorter bursts, which make it less useful for assets that are moving, such as people. It is, however, good for inventory control.
Right now, UWB is not quite ready for "prime time," due to the limited integration options, lack of providers and lack of people with the skill to handle what tends to be a complex technical challenge. The low signal range makes UWB installations particularly tricky. UWB is, thus, most useful if you need very high security or have a lot going on on frequencies close to the Bluetooth frequency, which can cause interference.
We saved this one for last for a reason. BLE stands for Bluetooth Low Energy. It uses the Bluetooth wireless protocol, which is standard in phones (and many other devices).
BLE can be used for both beacon use cases and tag and gateway. The "low energy" part means that BLE tags tend to last longer than active RFID tags, with their life limited by the battery in both cases. (Classic Bluetooth is known for having high consumption. Remember the days when turning Bluetooth on on your phone killed the battery quickly?)
BLE tags stay powered down until they need to transmit, have a solid range (as much as 100m) and while the tags are more expensive than passive RFID, they are cheaper than active RFID. They are also better suited to advanced applications such as temperature and humidity tracking.
Bluetooth Low Energy is, at current technology levels, a superior standard in many ways. It is essentially the only way to do customer-facing beacons (UWB is currently available only on one high-end smartphone and while it might replace Bluetooth as the standard eventually, that seems unlikely to happen any time soon). It integrates well with other technologies. Bluetooth 5 is backwards compatible with Bluetooth 4.2, and is recommended for new deployments for future proofing. (Bluetooth 5 gateways are available, but most smartphones are still on 4.2).
The batteries are also a little smaller than RFID batteries, making it easier to do tags that are an odd shape. While it can be expensive for large deployments, as accuracy relies on the number of gateways installed, and the price can add up, even reasonably more expensive smartphones are cheaper (and more versatile) than specialist RFID readers.
As you can see, Bluetooth wins for several use cases, and is your only option if you want the beacons or tags to be read using smartphones. New technologies might emerge in the future, but for right now if you are setting up a new system with no existing infrastructure, your best choice for expense and longevity is BLE. BLE is future proof, reasonably-priced and can give you the accuracy you need regardless of whether you are using a beacon-based system or a tag and gateway system for asset and employee tracking.
Kontakt.io is your source for BLE and location technology, whether you need extra tags, beacons, gateways or a full system. Contact us to find out how we can help with your project and the difficult design decisions you will have to make.