Bluetooth is a short-range wireless technology standard for exchanging data over short distances using radio transmissions in the 2.4 GHz band. It allows for ad-hoc connections between devices within 10 meters using frequency hopping spread spectrum and time-division duplexing. Bluetooth devices can connect in a piconet topology managed by a master device or scatternet topology connecting multiple piconets. The Bluetooth protocol stack includes layers for radio, baseband, link management, logical link control and adaptation, and various service protocols.

1. BLUETOOTH
IEEE 802.15.1

2. BLUETOOTH
 Universal radio interface for ad-hoc wireless connectivity.
 Short range (10 m), low power consumption, license-free 2.45 GHz
ISM band.
 Voice and data transmission, approx. 1 Mbit/s gross data rate.
 Wireless Personal Area Network (WPAN)
 FHSS and TDD
 Frequency hopping with 1600 hops/s
 Hopping sequence in a pseudo random fashion, determined by a
master
 Time division duplex for send/receive separation

3. Piconet

4. Scatternet

5. Bluetooth Protocol Stack  Radio
 Baseband
 Link manager protocol
 Logical link control and adaptation
protocol (L2CAP)
 Service discovery protocol
Core Protocols of Bluetooth

6. RADIO LAYER
 It only defines the carrier frequencies and output power.
 A frequency-hopping/time-division duplex scheme is used for transmission,
with a fast hopping rate of 1,600 hops per second.
 The time between two hops is called a slot, which is an interval of 625 μs.
 Each slot uses a different frequency.
 Bluetooth uses 79 hop carriers equally spaced with 1 MHz.
 Bluetooth transceivers use Gaussian FSK for modulation.

7. BASEBAND LAYER
Frequency selection during data transmission
(1, 3, 5 SLOT PACKETS)

8. BASEBAND PACKET FORMAT
 Bluetooth offers two different types of links,
 Synchronous connection-oriented link (SCO)
 Asynchronous connectionless link (ACL)

9.  SCO (Synchronous Connection Oriented) – Voice
 Periodic single slot packet assignment, 64 Kbit/s full-duplex, point-to-point
 ACL (Asynchronous Connectionless) – Data
 Variable packet size (1,3,5 slots), asymmetric bandwidth, point-to-multipoint

10. LINK MANAGER PROTOCOL
BASEBAND STATES OF A BLUETOOTH DEVICE

11. LOGICAL LINK CONTROL AND
ADAPTATION PROTOCOL (L2CAP)
 Simple data link protocol on top of baseband
 Connection oriented, connectionless, and signaling channels
 Protocol multiplexing
 Segmentation & reassembly

12. SECURITY