Bluetooth Technology

1. Bluetooth
Swapnil Bangera
Mobile & Wireless Communication
ME-EXTC

2. Contents
• Introduction
• Various Terms in Bluetooth
• Classes of Bluetooth
• Network Establishment in Bluetooth
• Modes of Operation
• Security Features of Bluetooth
• Bluetooth Security Levels
• Applications
• Advantages
• Disadvantages
• Conclusion

3. Introduction
• Bluetooth is a short-range and low power wireless technology originally
developed for exchanging data over short distances from fixed and mobile
devices, creating personal area networks (PANs).
• It is named after Harald Blaatand.
• The name was adopted as a tribute to the tenth-century Viking Harald Blaatand
who peacefully united Denmark and Norway. Harald liked to eat blueberries,
which gave his teeth the coloration that lead to the nickname "Bluetooth.“
• Short-range radio frequency technology that operates at 2.4 GHz on an
unlicensed Industrial Scientific Medical (ISM) band. It is based on IEEE 802.15.1
standard.
• Effective range of Bluetooth devices is 10 meters.
• It was originally conceived as a wireless alternative to data cables.

4. Terms used in Bluetooth
• Piconet
• Scatternet
• Master unit
• Slave units
• MAC address
• Parked units
• Sniff and hold mode

5. Bluetooth Classes
Bluetooth devices are classified according to three different power classes, as
shown in the following table.
Class Maximum Permitted
Power (mW)
Range (m)
Class 1 100 100
Class 2 2.5 10
Class 3 1 1

6. Network Establishment in Bluetooth
• STANDBY mode
• Before any connection in a piconet is created, all devices are in STANDBY mode.
• In this mode, an unconnected unit periodically listens for messages every 1.28 seconds.
It listens the messages on a set of 32 hop frequencies defined for that unit. The device
is said to be wake-up when it listens to messages. When it does not listen to messages,
it is said to be in sleep.
• PAGE mode
• The connection procedure is initiated by any one of the device, which then becomes
master. A connection in made by PAGE message if the address is known.
• The master sends a train of 16 identical page messages on 16 different hop frequencies
defined for a device to be paged (slave).
• If no response is received, the master transmits a train on remaining 16 hop
frequencies in wake-up sequence i.e. when the slave listens on messages in STANDBY
mode.
• Maximum delay before master reaches is twice the wake-up period (2.56s) while
average delay is half the wake up period (0.64s).

7. • INQUIRY mode
• A connection is made by the master by an INQUIRY message followed by a subsequent
PAGE message if the address is unknown.
• The INQUIRY message is typically used for finding devices like public printers, fax
machines, and similar devices with unknown address.
• The INQUIRY message is similar to PAGE message, but may require one additional train
period to collect all responses.

9. Modes of Operation
SNIFF, HOLD and PARK modes are the three power saving modes of operation for
Bluetooth devices which are connected to a piconet. These modes are used when
no data is to be transmitted.
• SNIFF mode:
• The slave device listens to the piconet in this mode, but at a reduced rate. Thus
reducing its duty.
• The SNIFF interval is programmable and depends on application.
• HOLD mode:
• The master unit can put a slave unit into HOLD mode or a slave unit can demand to ne
put into HOLD mode.
• Data transfer restarts instantly when units transition out of HOLD mode.
• The HOLD is used when connecting several piconets or managing a low power device
such as temperature sensor.

10. • PARK mode:
• The device is still synchronized to the piconet but does not participate in traffic.
• PARKED devices have given up their MAC address and occasionally listen to the traffic
of the master to resynchronize and check on broadcast messages.
In the increasing order of power efficiency, the SNIFF mode has higher duty cycle,
followed by HOLD mode with a lower duty cycle, and PARK mode, with lowest duty
cycle.

11. Bluetooth Security Features
Bluetooth security supports authentication and encryption. Authentication verifies
who is at the other end of the link. Encryption ensures confidentiality of data. Even
if a third party hacks the data, it is in encrypted form and not in original form.
1. Pairing: When two devices communicate for the first time, there is a pairing
procedure. In this procedure, a secret key is generated. This key is shared by
both the devices. It is stored in each device. When the devices want to
communicate in future, there is no pairing procedure.
2. Security modes:
1. Non-secure: A device will not initiate any security procedure.
2. Service level enforced security: A device does not initiate security procedures before
channel establishment.
3. Link level enforced security: A device initiates security procedures before link set up
is completed

12. Bluetooth Security Levels
There are two kinds of security levels i.e. authentication & authorization
• Types of services: Different services have different service requirements. Some
services require authentication and authorization. Some services require only
authentication and not authorization. Some services don’t require both
authentication and authorization.
• Authentication: Authentication is performed after determining the type of
service. It cannot be performed when link is established. It is performed only
when connection request to service is submitted. It can be performed in both
directions : client authenticates server & vice versa.

13. • Authentication procedure
• Connection request to L2CAP is sent.
• L2CAP requests access from security manager.
• Security manager enquires the service database.
• Security manager enquires the device database.
• If necessary, security manager enforces the authentication and encryption procedure.
• The security manager grants access and L2CAP continues to set up the connection.

15. • Authorization:
Some services require manual authorization of the device after authentication only then,
these services can be accessed. This leads to the concept of trust. There are two kinds of
device trust levels:
• Trusted device: It has fixed relationship and unrestricted access to all services.
• Untrusted device: This device has been previously authenticated, a link key is stored,
but the device is not marked as trusted in device database.
• An unknown device is also an untrusted device. No security information is available for
this device.

16. Applications
• Replacing serial cables with radio links.
• Wearable networks/WPANs
• Desktop/room wireless networking
• Hot-spot wireless networking
• Medical: Transfer of measured values from training units to analytical systems,
patient monitoring
• Automotive: Remote control of audio/video equipment, hands-free telephony
• Point-of-sale payments: Payments by mobile phone

17. Advantages:
 Wireless
 Inexpensive
 Automatic
 Interoperability
 Low interference and energy consumption.
 Share voice and data
 Instant PAN
 Upgradeable
 Long lasting technology.
 Easy link establishment

18. Disadvantages
 Data rate and security
 More susceptible to Interception and attack
 Less range
 Average Speed
 Short Life

19. Conclusion
A global standard for data and voice
• Eliminates Cables.
• Low Power, Low range, Low Cost network devices.
• Bluetooth seems to have a bright future after reviewing its benefits and wide
use.
• Further improvements are planned to be made in
• Data Rates
• Power Reduction
• Range

20. THANK YOU!
Presented By
Swapnil Bangera
ME-EXTC