This allows
Bluetooth device manufacturers to design creative frequency hopping criteria in order to have product
differentiation. The hop rate is 1600 hops/sec.
A Bluetooth device can essentially operate in two modes: master and slave. The master device
controls the frequency hopping pattern, controls which other devices are allowed to transmit, and provides
synchronization information. A group of devices operating in this fashion comprise what is
called a piconet. For data applications, slave devices are only allowed to transmit in response to a
transmission from the master device. In voice applications, slave devices transmit periodically in their
designated time slots.
Bluetooth was initially deployed with version 1.0 specification transmitting with a basic data
rate of 1 Mbps. It was later enhanced to provide 2 and 3 Mbps using the Enhanced Data Rate (EDR)
modifications [34].
Physical layer links are formed only between master and slave devices in the piconet. Each
Bluetooth device has an address which is used for identification and consists of 48 bits in length.
We have already discussed the piconet scenario above; however, there are occasions where a
Bluetooth device is participating in two or more piconets; this is now called a scatter net.
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