1. Bluetooth Introduction The Bluetooth Technology
Why Bluetooth
History
The Bluetooth Technology
The Bluetooth Stack
Bluetooth in ad hoc networks

2. Introduction Why Bluetooth? Cable replacement between devices.
Supported by major companies.
Open Specification
Low power consumption
Connection can be initiated without user interaction.
Devices can be connected to multiple devices at the same time.

3. History The technology was born in 1994.
The first version was released July 1999.
The Bluetooth name comes from the Danish Viking Harald Blåtand.

4. The Bluetooth Technology
The Bluetooth Stack:

5. Radio
Bluetooth devices operate on 2.4 GHz Industrial Scientific Medical band (ISM band).
Unlicensed in most countries.
Interferences from:
Other radio frequency short-range techniques
Wireless local area networks (IEEE )
Random noise generators (microwave ovens)
Other Bluetooth units

6. Radio (cont.) Techniques to minimize packet loss: Frequency Hopping
Adaptive power control
Short data packets

7. Frequency Hopping Uses FHSS (Frequency Hopping Spread Spectrum)
Divides the ISM-band into 79 1-Mhz channels.
Communication between devices switches between available channels.

8. Frequency Hopping (cont.)

9. Power Control
Three power classes defined with max output power from 1 mW (Class 1) to 100 mW (Class 3).
Devices may be implementet with power control
Optimize power consumption
Decrease interference
Bluetooth provides three types of power classes. These classes provide power and range as
follows:
Type Power Level Operating Range
Class 3 Devices 100mW Up to 100 meters
Class 2 Devices 10mW Up to 10 meters
Class 1 Devices 1mW meters
Each has its usage. Class 1 is a cable replacement for a mouse or keyboard. Class 2 is to
connect a laptop to PDA, PDA to PDA, or laptop to laptop. Class 3 can compete with b
and could be used for all of the above, or it can provide wireless connectivity for a whole building.

10. Bluetooth Packet Structure

11. Baseband
Responsible for channel coding/decoding, timing and managing a Bluetooth link.
Master/slave
Devices in a connection are either master or slave.
Communication is only possible between a master and its slaves.
A master and the slaves are named piconets.
Scatternet; multiple piconets connected together.

12. Piconets and Scatternet

13. The Link Manager
Responsible for establishing, supervising and tear down connections and logical links.
Link controller states introduced to carry out these tasks.
States:
Standby
Inquiry / Inquiry Scan
Page / Page Scan
Connection

14. The Link Manager (cont.)
Inquiry
Used to detect all devcies in an unknown environment.
Page / Page Scan
Describes how connection is established.
Have to know the address of the other devices. Is usually achieved through inquiry.
Connection
Master and slaves are synchronized.
Connection is established.

15. Inquiry / Inquiry Scan

16. Page / Page Scan

17. Host Controller Interface (HCI)
Provided to ease the partition of the Bluetooth Stack across two processors.
Some systems will implement the baseband and link manager on the Bluetooth device and higher levels on the host processor.
The HCI is provided as an interface between these parts.

18. Logical Link Control and Adaption (L2CAP)
Deals with
multiplexing of different services
segmentation
reassembling of packets
Quality of Service

19. Profiles
Provide interoperability between devices from different manufacturers for specific services and use cases.
A profile defines
a selection of messages and procedures
gives an unambiguous description of communication between two devices.

20. Bluetooth in ad hoc networks
Bluetooth network infrastructure is of dynamic ad-hoc type.
It is constantly changing and depending on the movement of the devices.

21. Bluetooth in ad hoc networks (cont.)
Temporary networks.
Connect ”on-the-fly”.
Small wireless network called ”personal area network” (PAN).
Provide voice, data, eliminate cables, bridge networks.
Supports PDAs, mobile phones, printers, faxes, microphones.

22. Bluetooth in ad hoc networks (cont.)
The master can support up to 7 devices in its network.
Devices use the same frequency, but can be in multiple networks.

23. Security
Bluetooth provides security only over the radio link, from each device to all other devices.
Three security specifications:
Confidentiality
Authentication
Authorization

24. Bluetooth in the future
Bluetooth was originally intended to be a cable replacement,
but, has evolved to become an infrastructure for Personal Area Network (PAN)
2001: 10 million devices produced
2003: 70 million!