Transcript Bluetooth by Santosh Sam Koshy

Santos
Agenda
Need for Bluetooth
Brief History of Bluetooth
Introduction to Bluetooth
Bluetooth System Specifications
Commercial Bluetooth Solutions
Network of Bluetooth Devices
Data and Voice support
Security Issues in Bluetooth
Architecture of a Bluetooth System
References
Need for Bluetooth
Due to the widespread use of computers and other
electronic gadgets at home and at office, the work
place is now a labyrinth of wires, and will still get
worse.
This is a problem that has to be ministered as soon as
possible
The Solution:
Bluetooth
Cable Replacement
The Solution
History of Bluetooth
Named after a medieval Danish King
The Bluetooth Special Interest Group (SIG) was
founded in February 1998 by Ericsson, Intel, IBM,
Toshiba and Nokia
The Bluetooth specification version 1.0 was released
in July1999 and version 1.1 in February 2001
Introduction to Personal Area Networks
A typical office is equipped with a number of devices such as a
PC, laptop, printer, fax, modem and so on..
These devices are interconnected by wires for the purpose of
sharing information. They form a Personal Area Network
(PAN).
The PAN is an ad-hoc network because the number of nodes in
the network is not fixed at any time.
Administering to these networks will be easier in using radio
links for communication.
A number of technologies have been proposed for the same
such as Bluetooth, IrDA, IEEE-802.11.. Of which Bluetooth is
the most attractive choice
Bluetooth System Specifications
Operating Frequency
The Bluetooth operating frequency is 2400 – 2483.5MHz
Bluetooth radio uses Frequency Hopping and hops between
channels @ 1600 hops per second
Unless the receiver knows the hop sequence, it cannot receive
data
Bluetooth radios communicate using a time division duplex
(TDD) discipline.
More than 2 devices may share the medium, and is therefore a
TDMA
Thus it may be said that Bluetooth uses FH-TDD-TDMA
Bluetooth System Specifications (contd..)
Operating Range
The normal operating range for Bluetooth is 10 meters
The range is dependent on the power of the radio transmitter – the
higher the power, the higher the range
The Bluetooth specs define 3 classes wrt the operating range
Services Supported
Bluetooth supports both voice and data services
Since voice communication is done in circuit switching mode
and data communication is done in packet switching mode,
both types of connections are supported in Bluetooth
The link established for voice communication is a Synchronous
Connection Oriented (SCO) link, and the link established for
data communication is a Asynchronous Connection Less (ACL)
link.
Network Topology
In a PAN, a set of devices forms a piconet (a small
network)
In each piconet, there is on master, to which all other
devices (slaves) tune to.
The master decides the hop-frequency sequence and
the slaves synchronize with the master to establish
links
Any device can become a master/slave. for example, a
cellular phone can be master or slave to a desktop
Network Topology: Piconet
Forming a Piconet
Establishing A Connection
Master Slave Piconet
Scatternets
Commercial Bluetooth Solutions
Bluetooth headset
Bluetooth cordless phone
Bluetooth LAN access point
Bluetooth LCD projector
Bluetooth speakers
Core and Profile Specifications
The Core Specifications describe the details of the
various layers of the Bluetooth protocol architecture,
from the radio interface to the link control
The Profile Specifications are concerned with the use
of Bluetooth technology to support various
applications.
Each profile discusses the use of technology defined
in the core specifications to implement a particular
usage model
Why Profiles????
The purpose of a profile specification is to define a
standard of interoperability, so that products from different
vendors that claim support to a particular usage model will
work together.
Profile Specification
Cable Replacement
Wireless Audio
Bluetooth Protocol Stack
vCard
WAE
AT
TCS Bin
Commands
f
OBEX
WAP
SDP
TCS
UDP/TCP
IP
Core Protocols
Cable Replacement
PPP
Adopted
Audio
Control
RFCOMM
Logical Link Control and Adaptation Protocol (L2CAP)
Host Controller Interface
Link Manager Protocol
Baseband
Bluetooth Radio
Protocol Architecture
The core protocols form a five layer stack containing :
Radio
Specifies details of air interface, including frequency, the use of
frequency hopping, modulation scheme, and transmit power
Baseband
Concerned with the connection establishment within a piconet,
addressing, packet format, timing and power control
Link Manager Protocol (LMP)
Responsible for the link setup between Bluetooth devices and
ongoing link management
Protocol Architecture (contd..)
Logical Link Control and Adaptation Protocol (L2CAP)
Adapts the upper layer protocols to the baseband layer. Provides
both connectionless and connection-oriented services.
Service Discovery Protocol (SDP)
Device information, services, and the characteristics of the
services can be queried to enable the establishment of a
connection between two or more Bluetooth devices
Protocol Architecture (contd..)
RFCOMM is the cable replacement protocol included
in the Bluetooth specification. RFCOMM emulates a
serial port that is designed to make replacement of
cable technologies
Bluetooth specifies a telephony control protocol. TCS
BIN is a bit oriented protocol that defines the call
control signaling for the establishment of speech and
data calls between Bluetooth devices
Protocol Architecture (contd..)
The adopted protocols include
PPP
The point to point protocol in the internet is standard protocol for
transporting IP datagrams over a point to point link
TCP/UDP/IP
Foundation protocols of the TCP/IP protocol suite
OBEX
Protocol developed by the Infrared Data Association (IrDA), for the
exchange of objects
WAE/WAP
Bluetooth incorporates the above too
Bluetooth and OSI
Bluetooth Functional Block Diagram
Bluetooth State Transition Diagram
Standby
Page
Page
Scan
Inquiry
Scan
Master
Response
Slave
Response
Inquiry
Response
Connection
Inquiry
Bluetooth States
Standby
Default state. Only clock is running
Connection
The device is connected to the piconet as master or slave
Page
Device has issued a page. Used by master to activate and
connect to a slave
Page Scan
Device is listening for a page
Bluetooth States
Master Response
Master receives a page response from a slave
Slave Response
Slave responds to a page from master
Inquiry
Device has issued an inquiry
Inquiry Scan
Device is listening for an inquiry
Inquiry Response
Device that issued inquiry receives response
In a Jist
1.
2.
3.
4.
5.
6.
Device sends an inquiry using a special inquiry – hopping
sequence
Inquiry scanning devices respond by sending a packet
The inquiring device requests a connection to the device
that responded
Paging is used to initiate the connection with the selected
device
The selected device which has entered the page scan state
responds
It synchronizes with the master’s timing and FH sequence
References
 William Stallings, Wireless Communications and Networks,
Pearson Education, 2004
 Dreamtech Software Team, Cracking the Code, Hungry Minds
IDG Books India (P) Ltd, November 2001