Bluetooth WPAN Connectivity Topologies

The Bluetooth WPAN Piconet. A piconet is a WPAN formed by a Bluetooth device serving as a master in the piconet and one or more Bluetooth devices serving as slaves. A frequency-hopping channel based on the address of the master defines each piconet. All devices participating in communications in a given piconet are synchronized to the

microseconds microseconds microseconds

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The payload can be fragmented to fit into one, three, or five 625 microsecond slots.

The payload can be fragmented to fit into one, three, or five 625 microsecond slots.

68 - 72 bits______54 bits______0 - 2745 bits derived from a 24-bit address r (LAP) I

derived from a 24-bit address r (LAP) I

or or

Figure 13.3 Format for an over-the-air payload bearing Bluetooth WPAN packet. (From Figure 3, page 24, IEEE 802.15.1. Reprinted with permission, Ref. 6.)

or or

Figure 13.3 Format for an over-the-air payload bearing Bluetooth WPAN packet. (From Figure 3, page 24, IEEE 802.15.1. Reprinted with permission, Ref. 6.)

frequency-hopping channel for the piconet, using the clock of the master of the piconet. Slaves communicate only with their master in a point-to-point fashion under control of the master. The master's transmissions may be either point-to-point or point-to-multipoint. Usage scenarios may dictate that certain devices act always as masters or slaves. However, this standard does not distinguish between devices with permanent master and slave designations. A slave device during one communications session could be a master in another and vice versa.

The Bluetooth WPAN Scatternet. A scatternet is a collection of operational Bluetooth piconets overlapping in time and space. A Blue device may participate in several piconets at the same time, thus allowing the possibility that information could flow beyond the coverage area of a single piconet. A device in a scatternet would be a slave in several piconets, but master in only one of them. Figure 13.4 shows various ways that Bluetooth devices interconnect to form communicating systems.

Figure 13.5 shows the Bluetooth protocol stack.

Single Slave (Point-to-point)

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