Bluetooth Mesh and RTLS
The beauty of Bluetooth Low Energy devices is that they can be designed to be very small and run 24/7 on little to no power for a long time.
Bluetooth mesh provides the basic infrastructure to support the relay of messages from BLE tags over a network of mesh relay devices or nodes. Location of the tags is most commonly determined using received signal strength (RSSI) at three or more nodes, the position of which is known and allow tag position to be calculated using geometrical trilateration techniques. Location accuracy is dependent on individual silicon implementation of RSSI measurement, as well as the sophistication of post-processing algorithms applied to the calculation. In most cases, Echolo often sees an accuracy of down to one meter or less when working with RTLS and BLE 5 systems.
As it stands now, there are no specific mesh protocol fro RTLS within Bluetooth although some activities are beginning in the smart environment working group with initial effort around an FRD that predicates the use of the Bluetooth mesh profile. The application layer protocol for Bluetooth Mesh can coexist with other applications that allow the complete RTLS system to be built even when not all application profiles are standardized yet. Compatibility at the core Bluetooth LE stack layers is maintained so that integration with the mobile device ecosystem is possible. This is an essential advantage of Bluetooth LE over many competing for short-range wireless standards, just as the Bluetooth mesh profile also alludes to the use of a smart or even legacy phone as the provisioner to add a device securely to a Bluetooth mesh network.
RTLS is a much more demanding application than most IoT solutions due to the number of Bluetooth tags and the amount of traffic generated.
In general, RTLS is a much more demanding application than most IoT solutions due to the number of BT tags and the amount of traffic generated per tag in a typical deployment. In order to allow a typical RTLS deployment to work a number of connected devices or ‘Gateways’ would need to be statically deployed in order to replay the information gathered from the BT tags from the local site to a cloud service. Each advertisement received from the BT tags is saved and reviewed in real-time. This goes back to my early comments about using RSSI from three or more points to calculate location and distance from another object. Standardization efforts eventually will define an RTLS profile that standardizes on protocol right up to the gateway, and also makes use of new features provided by Bluetooth 5, such as the extended advertising packets and secondary advertising channels. This will enable the full potential of the Bluetooth mesh profile to be utilized with RTLS services.
Echolo continues to build and work with the latest Bluetooth Low Energy technology including Mesh and Mesh location (Mesh RTLS) because we understand that location services will become a key function of every IoT object, as is connectivity to the Internet.
