PRESENTED BY:
Debasmita Banerjee
Diganta Bhaduri
Debjyoti Bhattacharya
WHAT IS BLUETOOTH?
Bluetooth is a wireless technology standard for exchanging data over short distances from fixed and mobile devices.
The transmission/exchange takes place by building personal area networks (PANs).
BLUETOOTH IN ACTION
In the house In the Office
Home Security
On the Road
On our Car
HISTORY Bluetooth was invented in 1994 by Ericsson.
The company later started working with a larger group of companies called the Bluetooth Special Interests Group, or "SIG”, to develop the technology into what it is today.
Bluetooth is not owned by any one company and is developed and maintained by SIG.
The name Bluetooth came from a code name originally used by SIG for the project and is a reference to a 10th century Danish king named Harold Bluetooth, who was responsible for uniting Norway, Sweden, and Denmark.
THINGS YOU MUST HAVE FOR BLUETOOTH
Transceivers and Receivers that can send and receive data because they use Radio Waves.
MAC Address (Physical Address):
- Burnt on the NIC card by the manufacturer.
PIN Number
- To identify the user using the device.
A Piconet
A FHSS protocol
BLUETOOTH SPECIFICATIONS
WHAT IS A PICONET? A Piconet session is a communication link that
must be created between devices for devices to communicate with each other.
This is done when the MAC address and the PIN number match.
If two devices come onto contact with each other( 32 feet) the user will be prompted to initiate a communication session.
Users then can either deny or accept the request to initiate a session.
Only devices approved by the user can take part in the session.
Data will appear as noise to unauthorized devices.
(A great security feature).
MASTER – SLAVE CONCEPT
MASTER:- Device in Piconet whose clock and hopping sequence
are
used to synchronize all other devices (slaves) in it.
- It also carries out Paging procedure and also Connection
Establishment.
o SLAVE: - Units within the Piconet that are synchronized to the
master via its clock and hopping sequence.
- After connection establishment, Slaves are assigned a
temporary 3 bit member address to reduce the no. of
addressing bits required.
PICONET STRUCTURE
Master
Active Slave
Parked Slave
Standby
“FHSS” PROTOCOL
Bluetooth devices use a protocol called (FHSS) Frequency-Hopping Spread Spectrum .
Uses packet-switching to send data.
Bluetooth sends packets of data on a range of frequencies.
In each session one device is a master and the others are slaves.
The master device decides at which frequency data will travel.
Transceivers “hop” among 79 different frequencies in the 2.4 GHz baud at a rate of 1600 frequency hops per second.
The master device tells the slaves at what frequency data will be sent.
This technique allows devices to communicate with each other more securely.
TIME DIVISION DUPLEX SCHEME Bluetooth devices use a Time-Division Duplex (TDD) scheme. Channel is divided into consecutive slots (each 625 s) . One packet can be transmitted per slot. Subsequent slots are alternatively used for transmitting and
receiving.
- Strict alternation of slots b/t the master and the
slaves.
- Master can send packets to a slave only in EVEN slots.
- Slave can send packets to the master only in the ODD
slots.
THE PROTOCOL STACK
Baseband
Link Manager
L2CAP
RFCOMM/SDP
TCP/IP
Applications
Transport Protocol Group
Middleware Protocol Group
Application Group
TRANSPORT PROTOCOL GROUP
Radio Frequency(RF):- Sending and receiving modulated bit streams.
Baseband:- Defines the timing & framing.
- Flow control on the link.
Link Manager:- Managing the connection states.
- Enforcing Fairness among slaves.
- Power Management.
Logical Link Control &Adaptation Protocol:- Handles multiplexing of higher level protocols.
- Segmentation & reassembly of large packets.
- Device discovery & Operations.
MIDDLEWARE PROTOCOL GROUP
Service Discovery Protocol (SDP):- Means for applications to discover device info, services
and its characteristics.
RFCOMM:- Cable replacement protocol, emulation of serial ports
over wireless network.
TCP/IP: - Network Protocols for packet data communication &
routing.
APPLICATION GROUP
Consists of Bluetooth aware as well as un-aware applications.
PHYSICAL LINK TYPES
Synchronous Connection Oriented (SCO): - Point to Point Full Duplex between Master & Slave.
- Established once by master & kept alive till released by
Master.
-Typically used for Voice connection (to guarantee continuity).
- Master reserves slots used for SCO link on the channel to
preserve time sensitive information .
Asynchronous Connection Link (ACL): - It is a momentary link between master and slave.
- No slots are reserved.
- It is a Point to Multipoint connection.
- Symmetric & Asymmetric links possible.
SECURITY
Security Measures:
- Limited/Restricted Access to authorized users.
- Both Link Level Encryption & Authentication.
- Personal Identification Numbers (PIN) for device access.
- Long encryption keys are used (128 bit keys).
- These keys are not transmitted over wireless. Other
parameters are transmitted over wireless which in
combination with certain information known to the device,
can generate the keys.
- Further encryption can be done at the application layer.
BLUETOOTH IN THE MARKET...
PC cards, Cell phones, Head sets, Chip sets,…Features Cost
20 dBm (~100 m)Point-to-multipointNo Scatternet
Applications
File Transfer, Dial-Up NetworkingLAN access, Fax, …
169 $ ---200 $
0 dBm (~10 m)Point-to-multipointNo Scatternet
File Transfer, Dial-Up NetworkingLAN access, Fax, …
169 $ ---
Company
Toshiba,Motorola,Digianswer
IBM, TDK
3COM
10 m user-user; 100 m user-Base StationPoint-to-multipointSW- & FW-upgradeable
File Transfer, Dial-Up NetworkingLAN access, Fax, E-mailUnconscious connection
149 $
Nokia
10 m user-user; Point-to-pointConnectivity Battery for the cell phone
File Transfer, Dial-Up NetworkingLAN access, Fax, E-mailUnconscious connection
149 $
Ericsson, Sigma
10 m user-user; Point-to-point; ARM processor; USB; RFCOMM ports
Basic BT Radio stackEmbedded or Host stackProgrammable
500 $
1500$
ADVANTAGES OF BLUETOOTH
These have Replaced cables for transferring Information from one Electronic Device to another one.
These have decreased Strain like carrying phones while talking, making hands free to do another work.
This is cheaply Available.
It’s Mobility is also very Important as it doesn’t need any power outlet or Internet connection or any other items.
DISADVANTAGES OF BLUETOOTH
Data sent between two Bluetooth devices is very slow compared with Wi-Fi transfer Rate.
Range Of a Bluetooth Device is 15-30 feet depending upon the Device.
Security is Biggest Disadvantage as transfer takes place through radio waves and a hacker can easily hack it.
Battery usage is also a problem, it will make device out of power before it would have if Bluetooth was not powered on.
CONCLUSION
A new global standard for data and voice.
Eliminate Cables.
Low Power, Low range, Low Cost network devices.
Delivers Automatic synchronicity between devices.
Future Improvements:- Master-Slave relationship can be adjusted dynamically for
optimal resource allocation and utilization.
- Adaptive, closed loop transmit power control can be
implemented to further reduce unnecessary power usage.
REFERENCES
[1] Bluetooth Consortium : http://www.bluetooth.comhttp://www.ericsson.com/bluetooth/
[2] Bluetooth Tutorial :http://www.ee.iitb.ernet.in/uma/~aman/bluetoothhttp://www.palowireless.com
[3] G.F.Pedersen, P.Eggers, “Initial Investigation of the Bluetooth Link”, VTC, pp 64 – 70
THANK YOU