Now, we recently said that Bluetooth devices communicate with each other in a piconet or PAN. Devices within this piconet play one of two roles: they are either the master or one of the slaves. Now, the master of the piconet has the clock or hopping sequence that is used to synchronize all other devices, or the slaves, in the piconet. The unit that carries the paging procedure and establishes a connection is by default the master of the connection. The slaves are units within the piconet that are synchronized to the master via its lock and hopping sequences.

The Bluetooth topology can best be described as a multiple-piconet structure. Since Bluetooth supports, both, point-to-point and point-to-multipoint connections, several piconets can be established and linked together in a topology called a “scatternet,” a group of independent and non-sychronized piconets that share at least one common Bluetooth device. Bluetooth devices must have point-to-multipoint capability to engage in a scatternet communication. There may be no more than 50 fully loaded piconets in a scatternet.

Piconets, although uncoordinated, have frequency hopping occurring independently. Linked ad hoc, several piconets can be established with each piconet being identified by a different frequency-hopping sequence. All participants on the same piconet are synchronized to this hopping sequence. Synchronization of different piconets is not permitted in the unlicensed ISM band. However, Bluetooth units may participate in different piconets through Time Division Multiplexing (TDM), a method of putting multiple data streams in a single signal by separating the signal into many segments, each having a very short duration. Each of the individual data streams are reassembled at the receiving end based on its timing. By doing this, a unit is able to participate in a different piconet by being active in only one piconet at a time.

It is with its service discovery protocol that Bluetooth enables a much broader vision of networking. You can now create you own personal area networks, where all the devices in your life can communication and work together. Technical safeguards are put into place to ensure that a cluster of Bluetooth devices in public places, in something like an airport lounge or, say, some type of transportation terminal would not all the sudden start talking to each other.

If you have missed any section on the Bluetooth technology, the links below will guide you to more information.

What is Bluetooth?

Origin of Bluetooth

Bluetooth and Applications