Bluetooth by Santosh Sam Koshy

BluetoothbySantosh Sam KoshyAgendaNeed for BluetoothBrief History of BluetoothIntroduction to BluetoothBluetooth System SpecificationsCommercial Bluetooth SolutionsNetwork of Bluetooth DevicesData and Voice supportSecurity Issues in BluetoothArchitecture of a Bluetooth SystemReferencesNeed for BluetoothDue 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 BluetoothNamed 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 NetworksA 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 SpecificationsOperating Frequency

The Bluetooth operating frequency is 2400 2483.5MHzBluetooth radio uses Frequency Hopping and hops between channels @ 1600 hops per secondUnless the receiver knows the hop sequence, it cannot receive dataBluetooth radios communicate using a time division duplex (TDD) discipline. More than 2 devices may share the medium, and is therefore a TDMAThus it may be said that Bluetooth uses FH-TDD-TDMABluetooth System Specifications (contd..)Operating RangeThe normal operating range for Bluetooth is 10 metersThe range is dependent on the power of the radio transmitter the higher the power, the higher the rangeThe Bluetooth specs define 3 classes wrt the operating range

Services SupportedBluetooth 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 TopologyIn 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 linksAny device can become a master/slave. for example, a cellular phone can be master or slave to a desktopNetwork Topology: Piconet

Forming a Piconet

Establishing A Connection

Master Slave Piconet

Scatternets

Commercial Bluetooth SolutionsBluetooth headset

Bluetooth cordless phone

Bluetooth LAN access point

Bluetooth LCD projector

Bluetooth speakers

Core and Profile SpecificationsThe 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 modelWhy 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 SpecificationCable ReplacementWireless AudioBluetooth Protocol StackfAT CommandsBluetooth RadioBasebandLink Manager ProtocolLogical Link Control and Adaptation Protocol (L2CAP)RFCOMMTCS BinSDPAudioControlvCardOBEXWAEWAP UDP/TCPIPPPPHost Controller InterfaceTCSCore ProtocolsCable ReplacementAdoptedProtocol ArchitectureThe core protocols form a five layer stack containing :RadioSpecifies details of air interface, including frequency, the use of frequency hopping, modulation scheme, and transmit power

BasebandConcerned 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 devicesProtocol 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 devicesProtocol Architecture (contd..)The adopted protocols include

PPPThe point to point protocol in the internet is standard protocol for transporting IP datagrams over a point to point linkTCP/UDP/IPFoundation protocols of the TCP/IP protocol suiteOBEXProtocol developed by the Infrared Data Association (IrDA), for the exchange of objectsWAE/WAPBluetooth incorporates the above tooBluetooth and OSI

Bluetooth Functional Block Diagram

Bluetooth State Transition DiagramConnectionStandbyPagePageScanInquiryScanInquiryInquiryResponseSlave ResponseMasterResponseBluetooth StatesStandbyDefault state. Only clock is runningConnectionThe device is connected to the piconet as master or slavePageDevice has issued a page. Used by master to activate and connect to a slavePage ScanDevice is listening for a page

Bluetooth StatesMaster Response Master receives a page response from a slaveSlave ResponseSlave responds to a page from masterInquiryDevice has issued an inquiryInquiry ScanDevice is listening for an inquiryInquiry ResponseDevice that issued inquiry receives responseIn a JistDevice sends an inquiry using a special inquiry hopping sequenceInquiry scanning devices respond by sending a packetThe inquiring device requests a connection to the device that respondedPaging is used to initiate the connection with the selected deviceThe selected device which has entered the page scan state respondsIt synchronizes with the masters timing and FH sequence

ReferencesWilliam Stallings, Wireless Communications and Networks, Pearson Education, 2004

Dreamtech Software Team, Cracking the Code, Hungry Minds IDG Books India (P) Ltd, November 2001