Smart Places with Bluetooth Low Energy mesh
For end-to-end Internet of Things solutions, short range radio technologies such as Wi-Fi, ZigBee, LoRa and Bluetooth Low Energy (BLE) are often used for the last mile. We have developed a way to increase BLE network coverage using mesh.
Bluetooth was invented by Ericsson in 1994. Today, we are working together with the Bluetooth Special Interest Group (SIG) to extend the coverage of the technology from a star topology to a multi-hop mesh. At the Mobile World Congress 2016, we used a smart home prototype, pictured above, to demonstrate how this works.
In the smart home prototype, there is at least one BLE mesh node placed in each room. Due to the small scale of the prototype, we had to manually filter the messages in order to enable multi hop communication between the mesh nodes. The range of each transmission is shown in the figure below.
The mesh nodes control the lamps and alarms of the house, and also monitor the temperature and relative humidity. The house alarm system is guarded using magnetic contact. Blue LED indicates the alarm is activated. In the hall, a capillary gateway is installed. It works as the central logic units for the capillary network and also provides access to the Internet. Additionally, there is also a mesh node in the greenhouse. Because of the distance, it will be difficult to establish a direct connection between the gateway and the node in the greenhouse. However, by utilizing mesh, the message between the gateway and the green house can be relayed via the nodes in the kitchen and the living room.
More importantly, because of the capillary gateway, the mesh network can be accessed remotely by the user. For example, when the user gets close to home, a mobile phone can be used to automatically turn off the alarm. The lamps and other actuators can be controlled via the capillary gateway in the same way.
Eventually, by using a capillary gateway, we can easily integrate intelligence to make the deployed network – and by that any place where this type of network is deployed – smarter.
Anna Larmo and Jingcheng Zhang
Ericsson Research, Wireless Access Networks