Scatternet

What is Scatternet?
A scatternet is a type of network that is formed between two or more Bluetooth-enabled devices such as smartphones and newer household appliances. A scatternet consists of at least two piconets.

Bluetooth devices are peer units that act as slaves or masters. Scatternets are formed when a device in a piconet, be it a master or a slave, decides to participate as a slave in the master of another piconet. This device then becomes the bridge between the two piconets that connect the two networks.
In order for a scatter network to form, a Bluetooth unit must be sent as a slave to another piconet in order to become a bridge for both networks. If the master of one piconet is the bridge to another piconet, it acts as a slave in the other piconet, even though it is a master of its own piconet. The device that participates in both piconets can forward data between members of both networks.

However, the basic Bluetooth protocol does not support this type of relay, so each device's host software must manage it. With this approach it is possible to combine numerous piconets into a large Scatternet and to expand the physical size of the network beyond the limited range of Bluetooth. A Scatternet can thus support communication between more than eight devices, which is the limit for a piconet.

The value of scatternets is still being discovered, but communication between small robots could be a valuable feature. The robots could connect to each other, with one acting as masters and the other acting as slaves. Different piconet teams could create larger stray nets to better cover an area. This type of scatternet could have potential bomb disposal and search and rescue uses.