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Bluetooth

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Title: Bluetooth


1
Bluetooth Technology
  • E. Amir Ezzat Amir.ezzat_at_rashpetco.com

2
Lecture topics
  • Introduction (Name, Program, Description)
  • Why Bluetooth?
  • Bluetooth network topology
  • Physical links
  • Connection Establishment States
  • Connection Modes
  • Protocol Architecture
  • Security Modes
  • Frame format
  • Bluetooth devices classification
  • Adv. Dis-adv.
  • Summary

3
Whats With the Name?
  • King Harald Bluetooth (A.D. 940 to 985)
  • 10th century Viking king in Denmark
  • Credited for uniting the country (Denmark
    Norway) and established Christianity
  • This is one of two Runic stones erected in his
    capital city
  • The stones inscription says
  • Harald Christianized the Danes
  • Harald controlled the Danes

4
Bluetooth program
Bluetooth Special Interest Group (SIG) 5 founding
members
(Ericsson,
Nokia, IBM, Intel Toshiba)
5
What is Bluetooth?
  • 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.

6
Why Bluetooth?
  • Synchronization
  • between mobile and stationary devices
  • Data access points
  • Connecting mobile users to the internet using
    bluetooth access point
  • Dynamic networks
  • Piconets
  • 8 devices can be actively connected in
    master/slave configuration
  • Scatternets
  • Piconets can be combined to form providing
    unlimited device connectivity

7
General Description
  • Standard IEEE 802.15.1
  • Frequency 2.4 GHz (Unlicensed ISM band)
  • Channel no. 79
  • Channel width 1MHz
  • Spread Spectrum FHSS (1600 hops/sec)
  • Modulation technique GFSK
  • Data rate 1 Mb/s
  • Range 10 meters
  • Key features
  • Robustness
  • Simplicity
  • point-to-point connection
  • low power
  • low cost
  • point-to-multipoint connection

8
Bluetooth network topology
  • Piconet
  • Each piconet has one master and up to 7
    simultaneous slaves
  • Master device that initiates a data exchange.
  • Slave device that responds to the master.
  • Scatternet
  • Linking of multiple piconets through the master
    or slave devices
  • Bluetooth devices have point-to-multipoint
    capability to engage in Scatternet communication.

9
Piconet
  • Basic unit of Bluetooth networking
  • Master and one to seven slave devices
  • Master gives slaves its clock and device ID
  • Master determines channel and phase
  • All devices in a piconet hop together

MMaster PParked SSlave SBStandby
10
Scatternet
  • Formed by two or more Piconets
  • Master of one piconet can participate as a slave
    in another connected piconet
  • No time or frequency synchronization between
    piconets
  • Makes efficient use of bandwidth

S
S
P
P
SB
M
S
M
S
SB
SB
S
P
11
Physical links
  • Between master and slave(s), different types of
    links can be established.
  • Two link types have been defined
  • Synchronous Connection-Oriented (SCO) link
  • Asynchronous Connection-Less (ACL) link

12
Physical links
  • Synchronous Connection Oriented (SCO)
  • Support symmetrical, circuit-switched,
    point-to-point connections
  • Typically used for voice traffic.
  • Data rate is 64 kbit/s.
  • Asynchronous Connection-Less (ACL)
  • Support symmetrical and asymmetrical,
    packet-switched, point-to-multipoint connections.
  • Typically used for data transmission .
  • Up to 433.9 kbit/s in symmetrical or 723.2 kbit/s
    in asymmetrical

13
Connection Establishment States (i)
  • Standby
  • State in which Bluetooth device is inactive,
    radio not switched on, enable low power
    operation.
  • Page
  • Master enters page state and starts transmitting
    paging messages to Slave using earlier gained
    access code and timing information.
  • Page Scan
  • Device periodically enters page state to allow
    paging devices to establish connections.

14
Connection Establishment States (ii)
  • Inquiry
  • State in which device tries to discover all
    Bluetooth enabled devices in the close vicinity.
  • Inquiry scan
  • Most devices periodically enter the inquiry scan
    state to make themselves available to inquiring
    devices.

15
Connection Modes
  • Devices operate in standby mode by default until
    they become connected to a piconet
  • 4 Connection Modes
  • Active
  • Hold
  • Park
  • Sniff
  • Modes allow devices to adjust power consumption,
    performance, and the role of participants in a
    piconet

16
Active Mode
  • Device operates on high-power
  • Limited to 7 Active slaves for each master
  • Three bit address (AM_ADDR) given to each active
    slave
  • Device participates on channel
  • (Can Listens, transmits and receives packets)

17
Hold Mode
  • Device operates on low-power
  • Device keeps active member address
  • Device does not support ACL packets on the
    channel but may support SCO packets
  • Master and slave agree on a one time hold
    duration after which the slave revives and
    synchronizes with channel traffic

18
Sniff Mode
  • Very similar to hold mode
  • Slave only listens on specified slots
  • Master can only communicate during arranged
    sniff time slots

19
Park Mode
  • Operates in very low-power sleep
  • Eight bits address (PM_ADDR) given to each Parked
    slave
  • Device stays synchronized to channel
  • Master establishes a beacon channel and beacon
    interval when a slave is parked
  • Parked slave wakes up at regular beacon interval
    to Maintain synchronization
  • Active and Parked slaves can be switched in and
    out to allow many connections to a single piconet

20
Protocol Architecture
  • Bluetooth is a layered protocol architecture
  • Core protocols
  • Cable replacement protocol
  • Telephony control protocols
  • Adopted protocols

21
Protocol Architecture
  • Core protocols
  • Radio
  • Baseband
  • Link manager protocol (LMP)
  • Logical link control and adaptation protocol
    (L2CAP)
  • Service discovery protocol (SDP)
  • Cable replacement protocol
  • RFCOMM

22
Protocol Architecture
  • Telephony control protocol
  • Telephony control specification binary (TCS
    BIN)
  • Adopted protocols
  • PPP
  • TCP/UDP/IP
  • OBEX
  • WAE/WAP

23
Protocol Architecture
24
Core protocols
  • Radio
  • Uses 2.4 GHz ISM band spread spectrum radio (2.4
    2.4835 GHz)
  • Modulation GFSK (Gaussian Frequency Shift
    Keying)
  • Implements FHSS to mitigate interference
  • 1600 hops per second through 79 (1MHz channels)
    (Hops every packet)
  • In piconet all slaves follow the master for
    frequency hop sequence
  • Packets are pretty short and can be 1, 3, or 5
    slots long (a slot is 625µs)
  • Advantages
  • Free and Open to everyone worldwide
  • Disadvantages
  • Can be noisy

25
Radio Specification
  • Low Cost
  • Single chip radio (minimize external
    components)
  • Todays technology (Time
    division duplex)
  • Low Power
  • Low voltage RF (1 mW
    up to 100 mW)
  • Robust Operation
  • Fast frequency hopping 1600 hops/sec
  • Strong interference protection

Applications
IP
SDP
RFCOMM
control
Data
Audio
L2CAP
Link Manager
Baseband
RF
26
Core protocols
  • Baseband
  • Concerned with connection establishment within a
    piconet, addressing, packet format, timing and
    power control.
  • Provides in-order delivery of byte streams
  • Handles Frequency Hop Sequences for
    Synchronization and Transmission
  • Establishes Links
  • Synchronous Connection Oriented (SCO)
  • Asynchronous Connection-Less (ACL)
  • Provides functionality to determine nearby
    Bluetooth devices

27
Baseband
  • Audio
  • Interfaces directly with the baseband.
  • it does not go through L2CAP
  • Each voice connection is over a 64 Kbps SCO link.
  • Any two Bluetooth devices can send and receive
    audio data between each other just by opening an
    audio link

Applications
IP
SDP
RFCOMM
control
Data
Audio
L2CAP
Link Manager
Baseband
RF
28
Link Manager Protocol
  • Responsible for
  • Setup and Management of Baseband connections
  • Management and control connection states of a
    Bluetooth unit in a piconet
  • Handles the control and negotiation of packet
    sizes used when transmitting data
  • Controls the power modes and duty cycles of the
    Bluetooth radio device
  • Security aspects (Authentication and Encryption )

Applications
IP
SDP
RFCOMM
control
Data
Audio
L2CAP
Link Manager
Baseband
RF
29
Logical link Control and Adaptation Protocol
(L2CAP)
  • Performs 4 major functions
  • Managing the creation and termination of logical
    links for each connection through channel
    structures
  • Enforcing and defining QoS requirements
  • Adapting Data, for each connection, between
    application (APIs) and Bluetooth Baseband formats
    through Segmentation and Reassembly (SAR)
  • Performing Multiplexing to support multiple
    connections over a single common radio interface
    (multiple apps. using link between two devices
    simultaneously)

30
Logical link Control and Adaptation Protocol
(L2CAP)
  • L2CAP provides requested QoS if possible and
    notifies application if link can not support
    demands
  • QoS
  • Applications may demand QoS on specific
    parameters as
  • Token rate (bytes/second)
  • Token bucket size (bytes)
  • Peak bandwidth (bytes/second)
  • Latency (microseconds)
  • Delay variation (microseconds)

Applications
IP
SDP
RFCOMM
control
Data
Audio
L2CAP
Link Manager
Baseband
RF
31
Core protocols
  • Service discovery protocol (SDP)
  • handles device information, services, and queries
    for service characteristics between two or more
    Bluetooth devices.

Applications
IP
SDP
RFCOMM
control
Data
Audio
L2CAP
Link Manager
Baseband
RF
32
Cable Replacement Protocol (RFCOMM)
  • RFCOMM
  • Reliable transport protocol, works with parallel
    data by connecting to the lower layers via L2CAP
  • Provides emulation of serial ports control and
    data signals over the L2CAP protocol

Applications
IP
SDP
RFCOMM
control
Data
Audio
L2CAP
Link Manager
Baseband
RF
33
Telephony Control Protocol (TCS BIN)
  • TCS BIN
  • bit-oriented protocol that defines
  • the call control signaling for the establishment
    of voice and data calls between Bluetooth
    devices.
  • mobility management procedures for handling
    groups of Bluetooth TCS devices

34
Adopted Protocols
  • PPP
  • PPP is designed to run over RFCOMM to accomplish
    point-to-point connections.
  • PPP-Networking is the means of taking IP packets
    to/from the PPP layer and placing them onto the
    LAN
  • TCP/UDP/IP
  • used for communication across the Internet
    (bridge to the Internet).
  • most widely used protocol family in the world,
    appeared on numerous devices including printers,
    handheld computers, and mobile handsets.
  • Access to these protocols is operating system
    independent

35
Adopted Protocols
  • OBEX (OBject EXchange)
  • Session-layer protocol for the exchange of
    objects, providing a model for object and
    operation representation
  • provides the same basic functionality as HTTP but
    in a much lighter fashion, uses a client-server
    model and is independent of the transport
    mechanism.
  • defines a folder-listing object, which is used to
    browse the contents of folders on remote device
  • WAE/WAP
  • Bluetooth incorporates the Wireless Application
    Environment and the Wireless Application Protocol
    into its architecture.
  • The goal is to bring Internet content and
    telephony services to digital cellular phones and
    other wireless terminals

36
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

37
Security Implementation within the Architecture
  • Security modes 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.
  • Security levels 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

38
Frame format
  • Access code
  • Header
  • Data

39
Frame format
  • Access code
  • (72 bits) are used for synchronization and
    identification which identifies the master node

40
Frame format
  • Header
  • 54 bits header includes thee repeats of an 18-bit
  • Address (3-bits) identifies one of the eight
    nodes (slave address)
  • TYPE (4 bits) indicates
  • Frame type (ACL, SCO)

41
Frame format
  • FLOW (One bit) is set when the slave buffer is
    full
  • ARQN (One bit) Positive or negative
    acknowledgement
  • SEQN (One bit) Sequence bit Inverted for each new
    transmitted packet
  • HEC (8-bits) error detection code used to protect
    the packet header
  • The header repeats three times. If all headers
    are the same, the frame is accepted if differ
    error happened

42
Bluetooth devices classification
  • Bluetooth Smart Ready devices
  • Bluetooth Smart devices

43
Bluetooth Smart Ready devices
  • Are the most effective way to connect to billions
    of Bluetooth devices in market today.
  • Examples include phones, tablets,
    PCs, TVs, even set-top boxes
    and game
    consoles that sit at
    the center of your connected world.
  • These devices can efficiently
    receive data from Bluetooth Smart
    devices and let you do
    something with it,
    such as record and chart your morning
    run on your smartphone or let you
    control the
    temperature of your home from your tablet.

44
Bluetooth Smart devices
  • Are designed to gather a specific piece of
    information Ex. (Are all the windows on my house
    locked? what is my blood glucose level? how
    much do I weigh today?,.) and send it to a
    Bluetooth Smart Ready device.
  • Ex. include heart-rate monitors, blood
    glucose meters, smart watches, window and
    door security sensors, key fobs for your car,
    and blood-pressure cuffs, the opportunities are
    endless.
  • If you have a Bluetooth Smart device you want to
    connect to a phone, tablet, PC or TV.

45
Advantages Disadvantages
  • Advantages
  • Wireless (No cables)
  • No setup needed
  • Low power consumption (1 Milli wat)
  • Industry wide support
  • Disadvantages
  • Short range (10 meters)
  • Small throughput rates (Data Rate 1 Mbps)
  • Mostly for personal use (PANs)
  • Fairly Expensive

46
Summary
  • Introduction (Name, Program, Description)
  • Why Bluetooth? (Synchronization, Access point,
    Dynamic networks)
  • Bluetooth network topology (Piconet, Scatternet)
  • Physical links (SCO, ACL)
  • Connection Establishment (States Standby, page,
    page scan, Inquiry, Inquiry scan)
  • Connection Modes (Active, Hold, Park, Sniff)
  • Protocol Architecture (Core, Cable replacement,
    Telephony control, Adopted)
  • Security Modes
  • Frame format
  • Bluetooth devices classification (Smart Ready,
    Smart devices)
  • Adv. Dis-adv.

47
Thanks
  • E. Amir Ezzat Amir.ezzat_at_rashpetco.com
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