Bluetooth has been around for more than 2 decades. In all versions, of Bluetooth released the most significant version is 4.0 which introduced Bluetooth Low Energy (BLE) or Bluetooth Smart. BLE was targeted for low power, low bandwidth, lacking audio capability given its prime use being the wireless transfer of small amounts of data at the lowest power consumption. These new radios offer a raw data rate of 1M symbols per second, but with the overheads in protocols like L2CAP and GATT, the effective data rate is a maximum of 250kbps. The “Internet of Things” (IoT) came to prominence, as device OEMs looked to leverage increased short-range wireless connectivity for a myriad number of battery-powered devices, all built around the smartphone environment.

Bluetooth 5 addresses the new demands from evolving IoT applications in terms of increased range and speed through multiple enhancements to the BLE radio PHY, as well as an increase of maximum transmit power from +10 to +20dBm. In a sense, new radio PHY gives more range but at the expense of lower data transfer speed, and the other new PHY gives a 2x speed improvement which provides for efficient transfer of bulk data.

2x Data Rate

Bluetooth 5 introduces a new radio PHY called ‘LE 2M’ which doubles the raw BLE data rate to 2M symbols per second. This means that the BLE radio will operate for less time in transmitting data, which ultimately reduces power consumption thus increasing battery life. This is a major advantage for battery-powered IoT devices. This appeals to the IoT for wirelessly connected devices that are powered by small coin cell batteries.

4x Range

Bluetooth 5 also introduces another new, radio PHY called ‘LE Coded’ which is still 1M symbols per second, it uses a combination of lower packet coding of 125kbps or 500kbps. The LE Coded PHY allows the range to be quadrupled compared to Bluetooth 4 and the increase in maximum TX power to +20dBm, to give a potential 4x increase in range.

The benefit of it is that in buildings the wireless signals will have better penetration, in terms of power consumption, these packets are roughly 2 to 8 times longer duration, the longest being about 16 milliseconds, so there will be an increase in the power consumption, hence a significant decrease in the battery life.

BLE 5 Mesh

BLE 5 mesh networking allows many-to-many (m:m) device communication and is optimal for the creation of networks on a large scale. It is ideal for environmental monitoring, automation asset tracking and IoT devices that require thousands of devices to communicate simultaneously.

BLE mesh has several advantages for developers

Industrial-grade solutions: Industrial automation and commercial building are key markets for power-efficient mesh networks. Industrial solutions demand reliability security and expandability which is supported by the BLE mesh network.

Established, reliable technology: While choosing a wireless connectivity technology, selection criteria should more than just speeds and feeds to embrace an understanding of the added value the technology provides and the environment support available to you. Bluetooth is reliable with more than 90% global awareness.

Compatibility: multiple vendor’s compatibilities allow products from different to connect it is possible due to three major features.

  • full-stack implementation,
  • interoperability-centric specification approach,
  • time-tested interoperability tools and processes.

To use mesh networking protocols over BLE, the best way is to use SDK from module provider which includes BLE mesh networking protocols with API. To create a Bluetooth mesh networking device, compatible software and hardware are required. Bluetooth mesh networking requires Bluetooth LE 4.x or 5.0 stack, which supports the GAP Broadcaster and Observer roles, to both scan and advertise for advertising packets.

For mobile applications to use with BLE mesh networking products, the OS provides suitable APIs which allow an application to meet the requirements relating to BLE advertising packets defined in the Mesh Profile specification one must use the advertising bearer which is the preferred bearer in all cases. If the advertising bearer is not usable, mesh proxy protocol can be used which enables communication with mesh network via proxy node. The proxy protocol can be implemented on standard BLE GAP and GATT APIs.

Unlike wireless audio devices like speakers that use Basic Rate/Enhanced Data Rate (BR/EDR) which is designed for continuous connection and audio stream. BLE mesh is designed for short-burst wireless connection and ideal for many-to-many device communication. The other mesh topologies as compared to many-to-many are

  • point-to-point, used to create one-to-one (1:1) device communications, is ideal for data transfers, and is suitable to connect to gadgets, such as fitness trackers and health monitors.
  • the broadcast used to establish one-to-many (1:m) device communications, optimizes information sharing and is ideal for beacon solutions especially for people with visual impairment and way-finding services.

Nodes of Bluetooth mesh network operate at the lowest power as compared to that of other similar devices and sensors. They wake up only when they have to transmit data like temperature or humidity readings. This allows for lower the power consumption  

BLE operates a flood-based message relay approach, with a managed flood approach to message relay meets the requirements for enabling reliable mesh networks and no complex routing table creation and management is required. Managed flood messaging is inherently multipath, ensuring messages reach their intended destination. It is also peer-to-peer, allowing all nodes to communicate directly with one another. With no central hub, there is no point of failure.

Security in Bluetooth mesh network

  • Devices added to a network are provisioned by using security algorithms. It uses 256-bit elliptic curves and out-of-band authentication to add devices in the mesh.
  • Communication is secured using AES-CCM 128-bit keys. All messages are encrypted and authenticated.
  • Two layers for encryption and authentication, the network layer and the application layer.
  • Every message has 64-bits of authentication which can be up 1088 bits for the longest messages.
  • Replay attacks are prevented by assigning fresh sequence numbers on every message sent.
  • Devices can be blacklisted in the network by using defined key update procedures.
  • Messages protect identity by obfuscating every packet sent and refreshing privacy. This means that if using mesh network devices while walking, people sniffing mesh packets cannot track you.

Applications

Bluetooth mesh network has application in the automation market, especially with commercial lighting solutions, and in sensor network solutions across several markets. It is ideal for IoT solutions that require thousands of devices to communicate with one another simultaneously.

Using Bluetooth technology, you can bring value-added capabilities to your products, such as beacon support for localized information and asset-tracking and way-finding services. Bluetooth has cultivated a mature ecosystem to ensure you can find the best enabling technology at the right cost.