The relationship between Bluetooth BLE and Bluetooth Mesh

Bluetooth Mesh is not a wireless communication technology, but a network technology. The Bluetooth Mesh network relies on Bluetooth Low Energy. Bluetooth low energy technology is a wireless communication protocol stack used by Bluetooth Mesh.

The Bluetooth low energy device can be set to broadcast mode and work in a connectionless manner. The data broadcast by it can be received by any other Bluetooth host device within the broadcast range. This is a 'one-to-many' (1:N) topology, where N can be a very large number! If the device that receives the broadcast does not perform data transmission, the radio frequency spectrum of the broadcast device is only for itself, and there is no clear limit on the number of other devices that can receive and use its broadcast. The Bluetooth Beacon is an excellent example of the Bluetooth broadcast function.

Bluetooth Mesh is based on Bluetooth BLE low energy broadcast

Bluetooth Mesh uses the Bluetooth low energy broadcast method to send and receive information, and forward information from a certain node in the network to the destination node. In the Bluetooth Mesh networking, this broadcast mode is also called network flooding.

Using network flooding, through controllable flooding message transmission, there is no need to create and manage complex routing tables, routing discovery tables, etc., which saves the overhead of maintaining the memory space for network operation. At the same time, the nature of network flooding message propagation is multi-path, which ensures that information can be transmitted to the destination node through multiple paths. Therefore, any single point failure in the network will not cause fatal network transmission. Impact, this makes the network highly reliable.

Low-power nodes and Friend nodes

In the Bluetooth Mesh network, low-power nodes can achieve low power consumption by reducing the duty cycle of the RF transceiver. These low-power nodes will only turn on the radio when they need to send and receive messages. The transceiver is in a sleep state at other times.

There is also a type of node in the Bluetooth Mesh network that is dedicated to low-power nodes. It has Friend characteristics and can also be called Friend nodes. Friend nodes and low-power nodes can establish a Friendship relationship. After establishing this relationship, the Friend node can temporarily store the information sent to the low-power node, and then retrieve the relevant information from the Friend node after the low-power node exits the sleep mode. In practical applications, Friend nodes can be light bulbs, set-top boxes, and routers. These devices are powered by mains and are not very sensitive to power consumption; low-power nodes can be battery-powered devices, such as sensors.