Bluetooth scope widens mesh specification
Mesh networking via Bluetooth is a long-awaited addition to the Internet of Things (IoT) connectivity space. Bluetooth technology is today present in billions of smartphones, tablets and other consumer electronics devices, but the use is limited to local communication. With the Bluetooth Mesh Profile, a wide range of new applications is enabled in residential and commercial building automation markets currently dominated by Zigbee, Wi-Fi, and proprietary technologies. Is Bluetooth Mesh up to the job?
Our view on Bluetooth Mesh
- Bluetooth Mesh networking specifications are now available and the first products will soon reach the market. Considering the large Bluetooth footprint, the standard has the potential to be quickly adopted by the market.
- Bluetooth Mesh supports the operation of dense networks with thousands of devices in the same network, which is impractical for competing technologies where coordination and/or scheduling is required.
- Bluetooth Mesh meets high expectations placed upon it and provides the robustness and quality of service needed for example in a building automation deployment, which is one of the targeted use cases. At the same time, the networking design is flexible and ready for future enhancements, targeting an optimization of the forwarding behaviour and automation of the relay selection process.
Why Bluetooth Mesh?
Bluetooth technology enjoys high levels of global consumer awareness, a global ecosystem of smartphones and tablets, and a 20-year history of delivering specifications, tools and processes to ensure global, multi-vendor interoperability. For these reasons, the long-awaited launch of Bluetooth Mesh casts a long shadow over the vast and crowded arena of IoT solutions.
Bluetooth Mesh provides a complete full-stack connectivity solution for mesh networking, where everything from radio aspects to the high-level service definition layer is fully specified.In Bluetooth Mesh, thousands of nodes can communicate reliably and securely within the same network and there is no single point of failure. The Bluetooth Mesh Profile builds upon Bluetooth Low Energy (BLE) technology and can work on devices already on the market.
The relaying of messages over multiple hops facilitates communication between nodes outside of the direct radio range and enhances the effective communication range compared to single-hop Bluetooth topologies. Therefore, Bluetooth Mesh can address a wide range of new use cases, including scenarios covering both large scale and dense deployments such as office buildings, hospitals, and airports.
As discussed in our earlier posts on Bluetooth Mesh and IoT Networking, it offers a competitive short-range radio option for connecting and managing smart objects via capillary gateways. Moreover, smartphones with built-in Bluetooth support can be part of the mesh, may be used to configure devices and act as capillary gateways.
Ericsson engineers invented Bluetooth in 1994 and the company is today a promoter member of the Bluetooth Special Interest Group. We have actively participated in the definition of the architecture and the development of the Mesh specification. The standardization team within Ericsson Research provided ideas and standard contributions, focusing on energy efficient operation, security, and mechanisms for scalable performance – all of which are key differentiators.
Design principles and distinct advantages
Unique characteristics of Bluetooth Mesh include the following:
- A publish/subscribe model is used to exchange data within the mesh network. It allows for flexible address assignment and group casting.
- Messages are authenticated and encrypted using a dual-layer security scheme. A network key provides security for all communication within the mesh and an application key provides confidentiality and authentication of the data. For example, a light bulb will not be able to unlock doors, even if the unlock command needs to be routed through the light bulb to reach the lock.
- A managed flooding method is used to forward messages. Bluetooth Mesh relays use a message cache to avoid forwarding the same message multiple times and there is a limit on the maximum number of hops.
- Neighboring devices use a broadcasting approach to exchange data. After initial provisioning, devices can simply start communicating and do not need to pair or establish connections with other devices.
- Devices needing low power support can associate themselves with an always-on device that stores and relays messages on their behalf, using a concept known as Friendship. Low power nodes can sleep uninterrupted for up to four days and are still able to send and receive messages in the mesh network.
- Mesh messages can be exchanged also over legacy Bluetooth connectivity, so that devices, such as today’s smartphones, that do not support the full mesh stack can still be part of the network.
A Bluetooth Mesh consisting of devices capable of communicating with each other, some using a friendship relationship in order to preserve battery power and proxies that can provide mesh connectivity over legacy BLE connections.
Case study: Bluetooth Mesh in large scale deployments
We performed a full stack implementation of Bluetooth Mesh in our system-level simulator to support standardization, validate implementation recommendations, and assess the performance of a Bluetooth Mesh network comprising hundreds of devices.
The study, which we detailed in our Ericsson white paper Bluetooth mesh networking, suggested that, with proper deployment and configuration of relevant parameters of the protocol stack, Bluetooth Mesh achieves a high level of quality of service even with demanding application requirements.
Learn more about Bluetooth Mesh networking on the Bluetooth Special Interest Group website.
The work on the evaluation of IoT connectivity options is supported by the EIT Digital project HII ACTIVE.