Bluetooth technology, Lecture notes of Network Design

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Bluetooth Wireless TechnologyJamel LynchSr.Consultant/ Architect, [email protected] 543 6421

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Agenda

Bluetooth Overview What is Bluetooth? What isn’t Bluetooth? Bluetooth Air Interface Bluetooth Protocol Stack Bluetooth Profiles Bluetooth Security

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What is ‘Bluetooth’?

The term Bluetooth refers to an open specification for a technology to enable short-range wireless voice and data communicationsanywhere in the world. It is the fastest growing standard ever proposed.

Over 2,800 companies have signed up to be adopters of theBluetooth specification.

In 1994 Ericsson initiated study to investigate the feasibility of a lowpower, low cost, short range radio interface between mobile phonesand their accessories.

Aim - eliminate cables between mobile phones and PC Cards.

1998 - Ericsson, Nokia, IBM ,Intel, Toshiba formed a

SIG.

CABLES

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Why is it called ‘Bluetooth’?

The Origin of the Bluetooth name:

Named after Herald Bluetooth, the Viking King whoChristened, united and controlled Denmark andNorway in the 10th century. King of Denmark 940 - 981 Bluetooth Wireless technology will unitemobile electronic devices of the world.

7

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© 2003 IBM Corporation

Bluetooth Industry Timeline

4Q

3Q

Current

1Q

2Q

4Q

Specification Standard

V1.2 Spec. Ratification

Minor spec. releaseAFH (Adaptive FrequencyHopping)No radio HW nor driverimpactsFW update onlyBackward compatible

BT v1.

V2.0 Spec Release

Major releaseHigher BW

- MR: 2Mbps- HR: 10Mbps

HW update (radio) New Profiles

BTv2.

New Feature Spec

BTv1.

Core Spec^ 2.4GHz721kbps IEEE 802.

BTv1.

802.15.

Bluetooth v1.1Ratified (MAC & Phy) IEEE future efforts abandoned

1H

2H

Ratification& Product

Ratification& Product

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Bluetooth Technology Summary

Globally free spectrum

2.45 GHz, ISM band GFSK modulation Frequency Hopping (1600 hops/sec)

Range

10m piconet (0dBm) 100m optional (+20dBm)

Data and voice capable (1Mbps)

Full duplex: 478kbps, Asymmetric 721kbps

Secure

Authentication 128 Encryption Limited Signal range 0 - dBm Pseudo Random hop sequence

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What does Bluetooth provide?

Provides point-to-point connections. Provides ad-hoc networking capabilities. Bluetooth specification details how the technology works. Bluetooth Profiles detail how specific applications work toensure interoperability.

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Master /Slave Bluetooth Network Topology

• 1 master and up to 7 slaves per piconet.• scatternet is not yet supported.

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Point-to-Multi-Point: The Piconet

Two devices create a point-to-point connection.

A third device comes into range.

The new device is discovered.

is added to the piconet and data can be transferred.

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Point-to-Multi-Point: The Piconet

Up to seven slaves can be connected to one master. Slaves cannot pass data to other slaves without sendingthrough the master. The master defines the timing for the piconet.

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Identifying Bluetooth Devices

Each Bluetooth device is assigned a unique 48-bit MACaddress by the Bluetooth SIG. This is enough addresses for 281,474,976,710,656Bluetooth units, this should last a few years even with theoptimistic predictions of the analysts! The address is split into three parts:

LAP: Lower Address Part - used to generate frequency hoppattern and header sync word. UAP: Upper Address Part - used to initialise the HEC andCRC engines. NAP: Non-significant Address Part - used to seed theencryption engine.

LAP

[0:23]

UAP

[24:31]

NAP

[32:47]

lsb

msb

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Bluetooth Channels

A master can create two types of logical channel with a slave device:

Asynchronous Connection Less (ACL): Packet Switched Systemprovides a reliable data connection with a best effort bandwidth;depends on radio performance and number of devices in thepiconet. Synchronous Connection Oriented (SCO): Circuit SwitchedSystem provides real time unreliable connection with a guaranteedbandwidth; usually used for voice based applications.

The Bluetooth connections are limited to 1Mbps across the air. This gives a theoretical maximum of ~723kbps of useable data.

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The Air Interface and Bluetooth Baseband

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The ISM Band

Bluetooth uses the 2.4GHz ISM frequency band. The Industrial, Scientific and Medical (ISM) band is anunlicensed band, I.e. any one can use it provided theydon’t exceed certain power constraints. The 2.4GHz ISM band is unlicensed all over the worldwhich makes Bluetooth the only completely world widestandard. Bluetooth uses the frequency range 2.4000 - 2.4835GHz.