Agenda
Bluetooth Overview
What is Bluetooth?
What isn’t Bluetooth?
Bluetooth Air Interface
Bluetooth Protocol Stack
Bluetooth Profiles
The term Bluetooth refers to an open specification for a technology to enable short-range wireless voice and data communications
anywhere in the world.
It is the fastest growing standard ever proposed.
Over 2,800 companies have signed up to be adopters of the Bluetooth specification.
In 1994 Ericsson initiated study to investigate the feasibility of a low power, low cost, short range radio interface between mobile phones and their accessories.
Aim - eliminate cables between mobile phones and PC Cards. 1998 - Ericsson, Nokia, IBM ,Intel, Toshiba formed a SIG.
The Origin of the Bluetooth name:
Named after Herald Bluetooth, the Viking King who Christened, united and controlled Denmark and
Norway in the 10th century. King of Denmark 940 - 981
Bluetooth Wireless technology will unite mobile electronic devices of the world.
IEEE formed a working group (802.15) to develop standards for WPAN.
IEEE approved IEEE 802.15.1 standard for PANs SIG provided BT spec 1.1 to IEEE 802.15 as a candidate for an IEEE 802 WPAN.
IEEE licensed wireless technology from the BT SIG. IEEE Adoption
Collaboration between standards organization and SIG improve specification.
Further strengthens the position of Bluetooth as the de-facto WPAN standard.
Formally elevates BT from industry spec into the realm of an official industry standard.
BT will be better accepted in the US once one can refer to it as an IEEE standard.
4Q03 3Q04 Current 1Q04 2Q04 4Q04 S p eci fication Standard V1.2 Spec. Ratification
Minor spec. release AFH (Adaptive Frequency Hopping)
No radio HW nor driver impacts FW update only Backward compatible BT v1.2 V2.0 Spec Release Major release Higher BW - MR: 2Mbps - HR: 10Mbps HW update (radio) New Profiles BT v2.0
New Feature Spec
BT v1.1 2.4GHz 721kbps Core Spec IEEE 802.15 BT v1.1 802.15.1 Bluetooth v1.1 Ratified
(MAC & Phy)
IEEE future efforts abandoned
1H05 2H05
Ratification & Product Ratification
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
Form factors
PC Card
Compact Flash USB devices Mini-PCI
Secure Digital cards ultraport
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 to ensure interoperability.
Master /Slave Bluetooth Network Topology
• 1 master and up to 7 slaves per piconet. • scatternet is not yet supported.
Point-to-Point (Piconet)
Two devices locate each other.
Form a connection and transfer data. “Wireless cable replacement” scenario.
The device that initiates the connection is called the Master.
Any other devices the Master is connected to are referred to as Slaves.
Point-to-Multi-Point: The Piconet
¾ Two devices create a point-to-point connection.
¾ A third device comes into range.
¾The new device is discovered.
Point-to-Multi-Point: The Piconet
Up to seven slaves can be connected to one master.
Slaves cannot pass data to other slaves without sending through the master.
Piconet-to-Piconet: The Scatternet
Scatternets allow devices to be active in numerous piconets.
The device can be a slave in one piconet and a master in another. It cannot be a master in two piconets!
The device can act as a gateway from one piconet to another.
Identifying Bluetooth Devices
Each Bluetooth device is assigned a unique 48-bit MAC address by the Bluetooth SIG.
This is enough addresses for 281,474,976,710,656
Bluetooth units, this should last a few years even with the optimistic predictions of the analysts!
The address is split into three parts:
LAP: Lower Address Part - used to generate frequency hop pattern and header sync word.
UAP: Upper Address Part - used to initialise the HEC and CRC engines.
NAP: Non-significant Address Part - used to seed the encryption engine.
LAP [0:23] UAP[24:31] NAP [32:47]
A master can create two types of logical channel with a slave device: Asynchronous Connection Less (ACL): Packet Switched System provides a reliable data connection with a best effort bandwidth; depends on radio performance and number of devices in the piconet.
Synchronous Connection Oriented (SCO): Circuit Switched
System provides real time unreliable connection with a guaranteed bandwidth; 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.
What Bluetooth isn’t!
Bluetooth is not intended to compete with or replace 802.11b, they are complimentary technologies.
The data rates, usage scenarios and fundamental ethos behind them are all different!
It is unlikely to be used in corporate wireless LAN’s. It is not suitable for high data rate applications.
High is defined to be >600kbps this allows suitable margin for re-transmissions.
The ISM Band
Bluetooth uses the 2.4GHz ISM frequency band.
The Industrial, Scientific and Medical (ISM) band is an unlicensed band, I.e. any one can use it provided they don’t exceed certain power constraints.
The 2.4GHz ISM band is unlicensed all over the world which makes Bluetooth the only completely world wide standard.
Spectrum Usage
The 2.4GHz ISM band is a free for all for anyone who wants to use it.
Direct Radio waves Visible X-rays
Current 100 kHz – 300 GHz light
Extremely Ultraviolet Gamma
low frequency FM radio radiation rays
(ELF) 88-108 MHz Very
low frequency Microwaves (VLF) 300 MHz – 300 GHz
mediumwave radio 550-1600 kHz
Infrared longwave radio radiation 150-350kHz
Frequency in hertz (Hz)
kHz MHz GHz
0 102 104 106 108 1010 1012 1014 1016 1018 1020 1022
Bluetooth
•The 2.4GHz ISM Band is also used by:
• Microwave Ovens.
• Digital Cordless Phones. • 802.11b.
Overcoming Interference
Due to the unrestricted nature of the ISM band, Bluetooth must overcome interference from other systems and
minimise its interference on other systems.
Bluetooth does this by using a Frequency Hopping Spread Spectrum (FHSS) technique.
This spreads the RF power across the spectrum which reduces interference and the spectral power density.
Frequency Hopping Spread Spectrum - FHSS
Bluetooth splits the spectrum up into 79 1MHz wide channels with a small guard band at each end of the whole band.
The Bluetooth radio changes transmission frequency 1600 times a second.
The frequency hops follow a pseudo random
sequence that meets the power density requirements for the FCC and other regulatory bodies.
2.400 Frequency, GHz 2.402 2.480 2.483 Guard Band Guard Band
Hop Selection and Synchronisation
One frequency hop lasts 625us, this increment is called a time slot.
Each Bluetooth device has a clock circuit that counts frequency hops.
The address of the master of the piconet is used to seed a frequency hop calculation algorithm.
The phase of the hop sequence is defined by the Bluetooth clock of the master.
Device address and clock phase information is exchanged during connection negotiation.
The slave synchronises its own clock to the master’s during connection so that both devices change
The Bluetooth Clock
The Bluetooth Clock keeps each device synchronised to the Bluetooth slot timing.
28-bit free running clock clocked at 3.2kHz.
The clock must have an accuracy of +/-20ppm. Bits of importance:
C0: 312.5us - Twice slot rate or Inquiry rate.
C1: 625us - Slot rate.
C12: 1.28s - Inquiry scan period.
C27: ~23.3h - Clock wraps about once per day.
C0 lsb msb C1 C2 C12 C27
Modulation Scheme
During each hop, data is transmitted using Gaussian Frequency Shift Keying, G-FSK.
FSK uses two different frequencies to transmit a binary ‘1’ or ‘0’.
For Bluetooth the two frequencies are:
fc + for ‘1’
fc - for ‘0’ where fc = frequency of current hop and
Transmission Timing
A slave can only send data to the master after it has received a valid packet from the master.
Masters transmit in even numbered slots and slaves respond in the next odd numbered slot.
Single slot packets are less then 366us long to allow the synthesiser to retune to the next frequency hop.
Master
Slave
Bluetooth defines 3 power classes for devices:
Class 1: 0dBm to +20dBm (1mW to 100mW). Class 2: -6dBm to +4dBm (250uW to 2.5mW). Class 3: <0dBm ( <250uW).
These power classes translate in to approximate distances often used when discussing Bluetooth:
Class 1: 100 Meters. Class 2: 10 Meters. Class 3: <10 Meters.
Bluetooth & 802.11b interference
Bluetooth hops over the entire 2.4 GHz frequency band.
Bluetooth splits the spectrum up into 79 1MHz wide channels with a small guard band at each end of the whole band.
The Bluetooth radio changes transmission frequency 1600 times a second.
The frequency hops follow a pseudo random sequence that meets the power density requirements for the FCC and other regulatory bodies.
If there are other users in the band (802.11,Microwave, cordless phones) collisions are unavoidable.
Frequency, GHz Guard Band Guard Band Frequency Collision
Software
Protocol stack : allows devices to locate, connect and exchange data with each other.
Major components of the Bluetooth protocol stack
Application layer – actual applications that make use of BT links. Application, APIs.
Middleware layer – transport protocols needed for existing and new applications to operate over BT links. SDP,
RFCOMM.
Transport layer – composed of protocols designed to allow devices to locate and to create, configure and manage
both physical and logical links that allow higher layer applications to pass data through these transport
Architecture and Protocol Stack
RF Baseband Audio Link Manager LMPLMP L2CAPTCP/IP HID RFCOMM
Applications Data Con trol L o g ic a l L in k C o n tr o l & A d a p ta tio n P r o to c o l ( L 2 C A P ) S e g m e n ta tio n & R e a s s e m b ly M u ltip le x in g Q o S L in k M a n a g e m e n t P r o t o c o l ( L M P ) S e tu p a n d M a n a g e m e n t o f B a s e b a n d C o n n e c tio n s A u th e n tic a t io n & S e c u r ity F lo w c o n tr o l B a s e b a n d & M A C 4 8 b it IE E E a d d r e s s 3 b it c o n n e c tio n a d d r e s s P t- p t, P t- M p t lin k s P o w e r e ffic ie n t m o d e s L in k T y p e s : S C O A C L Software Software Firm wa re Firm wa re Hard wa re Hard wa re
What can you do with Bluetooth?
The Bluetooth specification defines a series of profiles that aid interoperability between similar devices.
The profiles describe applications and usage scenarios for common applications.
Application Profile Name
Serial Emulation Generic Serial
Ad-hoc Network LAN Access
Dial up w/ Phone DUN
File transfer FTP
FAX FAX
Audio Headset
Cable replacement technology
Keep your hands free with the ultimate solution for the:
Road Office Car
Dial Up Networking (DUN) Profile
Allows wireless connection from a PC to a mobile phone for remote LAN or Internet access.
Any PC should interoperate with any mobile phone in a secure fashion.
Profile interoperability is tested at qualification and voluntarily at UnPlug Fests.
The Conference Table
Create and share informations with your colleagues by forming small private work space
Collaborative work
File and resource sharing
GSM D-AMPS CDMA PSTN etc….
The Instant Postcard
Send instant photos and video clips from any location
Other Profile Examples
Electronic Business Card Exchange (OBEX)
& P.I.M. Synchronisation Personal Area
Networking (PAN)
Bluetooth Security
The BT system provides security measures both at the application layer and the application the link layer for usage protection and information confidentiality.
Four different entities are used for maintaining security at the link layer
A public address unique for each user Two secret keys
Emerging Technology
WLAN WWAN RFID SDR
Frequency band
- 802.11a - 5.15 GHz to 5.85 GHz - 802.11b/g- 2.412 GHz to 2.484 GHz Modulation
• - 802.11a and 802.11g: OFDM (54Mbps)
• - 802.11b : DBPSK,DQPSK, CCK (11Mbps)
Security
Data encryption: 64-bit, 128-bit, Wired Equivalency Protection (WEP)
802.1x EAP WPA
Wireless LAN - Standards
802.11b 802.11a 802.11h 802.11i 802.11e 802.11fModifications to comply with European regulations
Protocol for interoperability between WLAN access points
802.11g Speed: 54 Mbps Uses: 5 GHz band Eight non-overlapping channels Speed: 11 Mbps Uses: 2.4 GHz band
Three non-overlapping channels
Speed: 54 Mbps Uses: 2.4 GHz band
Three non-overlapping channels
Security and Authentication enhancements
QoS and CoS Mechanisms 802.11
Wireless WAN
Switching Technologies
Circuit Switching - an electrical physical didcated path that transmits ever-fluctuating voice or data signals. A dedicated path is established through every switch and transmission line needed to connect the call before the person being called ever hears the telephone ring.
Packet Switching - a virtual path for data switching. The addresses of the packets are read by the switches and routed to the approiate path. Bursts of data are sent only when needed allowing an "always on state"
Wireless Access Standards
Frequency Division Multiple Access (FDMA) - analog wireless transmission technology that allocates a single channel to one user at a time
Time Division Multiple Access (TDMA) - digital transmission technology that allows a number of users to access a single radio-frequency (RF) channel without interference by allocating unique time slots to each user within each channel.
Code Division Multiple Access (CDMA) - digital wireless spread spectrum technique allowing multiple
Wireless WAN
W W A N c o n n e c tiv ity re q u ire s a w ire le s s a c c e s s d e v ic e a n d a w ire le s s n e tw o rk in fra s tru c tu re , p ro v id e d b y a w ire le s s s e rv ic e c a rrie r.
C a rrie r - w ire le s s s e rv ic e p ro v id e r p ro v id in g s u b s c rib e r a c c e s s to th e n e tw o rk
S IM (s u b s c rib e r id e n tity m o d u le - G P R S o n ly ) - a u th e n tic a tio n to s e rv ic e p ro v id e r
W ire le s s A c c e s s D e v ic e - d e v ic e e n a b lin g a c c e s s to th e w ire le s s n e tw o rk
M o b ile P C
T h e w ire le s s a c c e s s d e v ic e s e n d s a n d re c e iv e s v o ic e a n d d a ta v ia ra d io w a v e s w ith ra d io to w e rs , w h ic h c a rry th e s ig n a l to a m o b ile s w itc h in g c e n te r, w h e re th e s ig n a l is p a s s e d o n to th e a p p ro p ria te p u b lic o r p riv a te n e tw o rk lin k . T h e s ig n a l c a n th e n b e tra n s fe rre d to a n
o rg a n iz a tio n 's e x is tin g n e tw o rk .
c a r rie r
W ire le s s A c c e s s D e v ic e M o b ile P C
