Until now, many solutions have been introduced for wireless mesh networks using various technologies. The initial goal was to create a reliable network for tactical military use cases. After that, the technology was used for industrial purposes, and later for smart buildings and homes. The main reason that implementations of mesh over WiFi and Zigbee have failed to gain mass adoption is lack of interoperability between vendors. So far, most of the solutions have been proprietary. The new Bluetooth mesh is about to change that.
The evolution of Bluetooth from personal area network to mesh network
Bluetooth started as a personal area network (PAN) technology. The point-to-point connectivity enabled pairing nearby devices and enabled convenient wireless connectivity for many things like computer input devices. It was especially successful in the audio market, enabling various wireless headsets. Bluetooth later evolved to include broadcasting capabilities, allowing one-to-many connectivity. This enabled positioning via beacons, which complemented the outdoor GNSS technology for indoor navigation, where satellites could not be relied upon. Throughout the releases of Bluetooth, it has consistently been augmented and improved to reach longer distances, achieve higher throughput, and increase power efficiency. Today, Bluetooth 5 is one of the best options for home and work building area networks, suitable for the emerging smart home market and industrial smart office and smart factory markets. Mesh networking, the latest addition to Bluetooth, is sure to be highly successful due to some significant advantages it has over earlier mesh solutions.
The four main advantages of Bluetooth compared to other mesh technologies
- Easily upgradeable - Bluetooth mesh can be supported with just a software upgrade from any Bluetooth low energy (BLE) version since BLE4.0. This also means that any device supporting BLE can connect to a mesh network with just a software upgrade. The combination of this feature with the ubiquity of Bluetooth technology gives Bluetooth mesh a critical advantage over the main competitor, 15.4-based ZigBee (and Thread). Every major smartphone and tablet will be able to securely connect to the Bluetooth mesh network. Users will be able to enjoy a simple and familiar control panel in their hand by simply downloading an app. In contrast, there is no trend to integrate Zigbee into such mobile devices.
- Future proof - Bluetooth mesh is the first worldwide mesh standard specified all the way up to the application. It is therefore not just a network technology. It comes with what are called Mesh Models, which can be seen as equivalent to legacy Bluetooth profiles, and which specifiy all the functions, controls, and behavior of a mesh device for a given application. This ensures interoperability between multiple vendors. It also ensures that the devices are future proof. For example, a light switch bought today is guaranteed to control a lightbulb purchased ten years from now.
- Low power - While mesh technology is generally not low power, Bluetooth mesh is surprisingly power efficient. In most cases, the mesh infrastructure is connected to the main power, but Bluetooth mesh is friendly with low power and battery-operated nodes such as light switches and temperature sensors. Indeed, on top of using the Bluetooth low energy flavor of the standard, the concept of Friendship has been introduced to cope with low power nodes. A low power node such as a temperature sensor, sending temperature every hour or whenever it reaches a certain threshold, can be attached to the mesh network. At any time, the user may want to update the thresholds from a smartphone while the sensor is in sleep mode. A ‘friend’ in the mesh network will actually buffer the commands and forward them to the temperature sensor as soon as it wakes up.
- Highly secure - Bluetooth mesh is highly secured, which is critical for IoT. All Bluetooth mesh messages are encrypted and authenticated at two levels: network and application. A Bluetooth mesh message relayed by a mesh node cannot be read by this mesh node if it is not the final destination. Only the node designated to receive the message can read it. Also, a new device cannot join the mesh network if it is not authenticated and shared with the right mesh network security key. Moreover, the network key may be refreshed from time to time, thanks to a secured key refresh procedure.
Wireless mesh is a successful and useful technology, but until now has suffered from lack of uniformity and interoperability between vendors. However, a standardized, low-power, highly secure version backed by a powerful group could be just the thing that was missing for mesh to flourish. The new Bluetooth mesh is the best mesh technology yet because it meets all these requirements. It has been under gestation and interoperability testing for quite some time before its ratification, and now it is ready to conquer the market. We are already seeing a strong interest from silicon vendors looking to implement mesh.