BluetoothBluetooth

Presenters: Group 6Allan Alarcon, Ingrid Anderson, Bhupesh Kapoor, Shi-Wu Lee

- Name given to this new technology, set to commercially come out this year - It is a cable-replacement technology

- Technically, is a chip to be plugged into computers, printers, mobile phones, etc. Designed by taking the information normally carried by the cable, and transmitting it at a special frequency to a receiver Bluetooth chip which will then give information received to these mobile devices.

History

History

The Bluetooth Special Interest Group (SIG) was founded by Ericsson, IBM, Intel, Nokia and Toshiba in February 1998 to develop as open specification for

short-range wireless connectivity.

Key Features:

Robustness, low complexity, low power and low cost

Main Strength:

Ability to simultaneously handle both data and voice transmissions such

as headset for voice calls.

Usage

Home: Having multiple PCs and need for networks that are simple to install and

maintain

Commercially: Handhelds and other mobile devices

Some System requirements:- Universal framework to access

information across a diverse set of devices

- Should offer similar protection as in cables. There should not be any

compromises on security- It should be simple, small and power

efficient for easy mobile usage

The standard requirement :- must enable the devices to

establish ad hoc connections.

Wireless connectivity over Bluetooth

Works with: Any laptop, handheld PC or PDA with a spare Type II PCMCIA slot

Operating Systems: Windows XP, Windows 2000, Windows 98, Windows 95 or Windows CE

Bluetooth Components

• Four major components:

° Radio Unit (radio transceiver)

° Baseband Unit (flash memory & CPU)

° Software Stack (driver software)

° Application Software (user interface)

Bluetooth Radio

• Radio transceiver supports spectrum spreading and operates at a

frequency between 2.402 GHz - 2.480 GHz ISM band.

• Spectrum spreading is accomplished by frequency hopping in 79

hops displaced by 1MHz. (maximum of 1600 hops/sec.)

• Each device can optionally vary its transmitted antenna power

Device Power Class

Max Output Power (mW)

Max Output Power (dBm)

Expected Range (?Obstructed Environment?)

Class 1 100mW 20dBm 100m

Class 2 2.5mW 4dBm 10m

Class 3 1mW 0dBm 10cm

Bluetooth Baseband

• Better term: “Link Controller Unit”

• Actual hardware unit which enables the physical link between devices

• Implements baseband protocols and Link Manager (LM) routines.

° link connection and power control

° asynchronous and synchronous links

° handles packets, paging and inquiry

° applies a time-division duplex scheme (alternate transmit and

receive)

Connection Establishment

• All devices are in Standby Mode by default, unconnected and

periodically scan for messages.

• 2 types of scans:

° Page Scan - device is listening for Data Access Code (DAC)

· used for set up connection

° Inquiry Scan - device is listening for Inquiry Access Code (IAC)

· used to discover which units are in range

Bluetooth Network Topology

• capable of point to point & point to multi-point connections

• Piconet:

° a master device

° one to seven active slave units

° a piconet channel

• Scatternet:

° a group of piconets, up to maximum of ten

° a way of connecting a device to multiple masters

° Full-duplex rate of more than 6Mb/s.

Link and Packet Types

• 2 types of physical links

° Synchronous Connection-Oriented (SCO)

· voice and data transmission, a point to point connection between a master and a specific slave

° Asynchronous Connection-Less (ACL)

· data transmission only, a point to multi-point connection between a master and all the active slaves

Bluetooth Capacities

• Bluetooth can support:

° one asynchronous data channel

· asymmetric link of 723.2 kb/s in either direction while permitting 57.6 kb/s in the return direction

·symmetric link of 433.9 kb/s

° up to three simultaneous synchronous voice channels

· each supports 64 kb/s in each direction

°one channel which simultaneously supports asynchronous data and synchronous voice

Note: D stands for Data , M stands for Medium rate , H stands for High rate (All rates are in Kbits/sec)

Packet Type Max Symmetric rate (two way)

Max Forward (Assymetric) rate

Max Reverse (Assymetric) rate

DM1 108.8 108.8 108.8

DH1 172.8 172.8 172.8 DM3 258.1 387.2 54.4 DH3 390.4 585.6 86.4

DM5 286.7 477.8 36.3 DH5 433.9 723.2 57.6 AUX1 185.6 185.6 185.6

Connection Modes

• 4 Connection Modes

° Active Mode: device is actively participating in a channel. It’s

assigned an Active Member Address (AM_ADDR)

° Hold Mode: maintains AM_ADDR. Supports synchronous but not

asynchronous packets

° Sniff Mode: maintains AM_ADDR. Supports both synchronous and

asynchronous packets

° Park Mode: no activity within a channel but remains synchronized to

a channel

Security Features

• specification includes security features at the link level.

• supports authentication (unidirectional or mutual) and encryption.

• devices transmit on the heavily used, unlicensed 2.45 GHz radio band ( the same used by microwaves.)

• to keep transmission from breaking up, frequency hopping is employed.

Security Features cont’d• Each Bluetooth device has a unique address

• Associating the ID with a person facilitates tracking

– i.e. individuals can be traced and their activities easily logged.

• For Bluetooth devices to communicate, an initialization process uses a PIN.

• While some devices allow users to punch in an ID number, the PIN can also be stored in the non-volatile memory of the device

Security Modes

• Bluetooth security is divided into three modes: – Security Mode 1: non-secure

– Security Mode 2: service level enforced security

– Security Mode 3: link level enforced security

Security Architecture

Security Implementation within the Architecture

• Two possible security Two possible security modes for devicesmodes for devices::

• Trusted Device

– Such a device would have access to all services for which the trust relationship has been set.

• Untrusted Device

– Such a device would have restricted access to services.

• Three levels of security for services:

• Authorisation Required

– access granted to trusted devices

• Authentication Required– the remote device must be

authenticated

• Encryption Required

– The link must be changed to encrypted mode, before access to the service is possible

Potential Weaknesses

• PIN code problems

• Spoofing due to non-secret link key

• Spoofing Bluetooth device addresses

• Limited transport in 2.4 GHz band. Mbps for BlueTooth. Need higher rate for Local Area Networks. (sending graphics to be printed)

• mutual perturbation (cross-talk) of corresponding office equipment within a same building

• frequency hopping provides some level of security, confidentiality may be compromised via currently available decoder technology.

• Bluetooth is WPAN (Wireless Personal Area Network) not LAN replacement. low cost, low profile, low power wireless link for convenience

• BT not designed for large file nor fast transfer; for mobility and convenience

• wireless devices always have security issues, but BT’s range is 10 meters need to be within this range to pick up transmission

Drawbacks Benefits

• Higher frequency 60GHz: a. free world wide b. less cross talk thus more confidentiality of transmitted information c. larger bandwidth than 2.4 GHz

• 60 GHz - Not Cost Effective (potentially higher cost of necessary adapters. Power drain and may be larger in size. BlueTooth designed to circumvent these issues. Cheap, low power, and convenient.

Drawbacks Benefits

Compatibility of BlueTooth: Upgrade to BT

PC's quite easy. Bluetooth PCMCIA cards, USB connectors etc. are developed at this stage, thus only a matter of installing the device, and loading up some bluetooth software

Upgrade PDA’s with BlueTooth add-on chips or buy PDA’s with chip already in place

current Mobile Phones may not be upgraded , due to their cheap cost and relativity limited complexity, and lack an interface for any kind of bluetooth device (such as a USB port). Although Ericsson will be offering a bluetooth chip add-on.

Future : Is it already here? Bluetooth vs Airport (802.11)

• 1MB/sec, 10 meters, 7 active devices

• can be used wherever you are – home, office or on the move. (PDA, mobile phone)

• Cheap; various applications to drive the price down (electronics, telecoms, automotive and computing)

• BT future revision may be as a high speed network solution

• 10 MB/sec, 50 meters, 10 active devices

• wireless networking only

• pricer

• higher speed wireless networking solution