King Harald Bluetooth unified warring Viking tribes in the 10th century. In the 21st century, a wireless Bluetooth network is named after him. Bluetooth allows for personal ad-hoc networks, cable replacement, and landline data/voice access through access points. It operates in the unlicensed 2.4GHz band using frequency hopping and supports data rates up to 1Mbps.

1. BLUETOOTH
Overview
Spanakis Manolis
Computer Science Department
CS-532
Where are
my shoes?
I am King Harold
Bluetooth who unified
warring Viking Tribes in
the 10th Century. In the
21st Century a wireless
Bluetooth network is
named after me.

2. Who is Bluetooth?
 Harald Blaatand “Bluetooth” II
• King of Denmark 940-981 AC
 This is one of two Runic
stones erected in his capital
city of Jelling
• The stone’s inscription (“runes”) says:
 Harald christianized the Danes
 Harald controlled the Danes
 Harald believes that devices shall
seamlessly communicate
[wirelessly]

3. What does Bluetooth do for
you?
Personal Ad-hoc
Networks
Cable
Replacement
Landline
Data/Voice
Access Points

4. Ultimate Headset

5. Cordless Computer

6. Automatic Synchronization
In the Office
At Home

7. Bluetooth SIG -- more
 February 1998: The Bluetooth SIG is formed
• promoter company group: Ericsson, IBM, Intel,
Nokia, Toshiba
 May 1998: The Bluetooth SIG goes “public”
 July 1999: 1.0A spec (>1,500 pages) is published
 December 1999: ver. 1.0B is released
 December 1999: The promoter group increases to 9
• 3Com, Lucent, Microsoft, Motorola
 February 2000: There are 1,500+ adopters
• adopters "enjoy" royalty free use of the Bluetooth
technology
 products must pass Bluetooth certification

8. The Bluetooth program
overview
Bluetooth
Promise
Wireless Connections Made Easy
Bluetooth
Values
Freedom, Simplicity, Reliability,
Versatility and Security
Usage
Scenarios
What the technology can do
Specification
Profiles
How to implement the usage scenarios
Certification
Testing
Interoperability
License free IP for adopters: product
testing to ensure interoperability;
protect the Bluetooth brand

9. General Description
 A cable replacement technology
 Operates in the unlicensed ISM band at 2.4
GHz
 Frequency Hopping scheme (1600 hops/sec)
 1 Mb/s symbol rate
 Range 10+ meters
 Single chip radio + baseband
 Key features:
 Robustness
 low complexity
 low power, and
 low cost.

10. General Description (2)
 Bluetooth supports
• Synchronous & asynchronous data channels.
 Three simultaneous synchronous voice channels, or
 One channel, with asynchronous data and
synchronous voice
• Each voice channel supports 64 kb/s in each direction.
• The channel can support maximal 723.2 kb/s
asymmetric (and still up to 57.6 kb/s in the
return direction), or 433.9 kb/s symmetric.
 Bluetooth provides
• point-to-point connection (only two BlueTooth
units involved), or
• point-to-multipoint connection.

11. New Application Scenarios
 Data Access Points
 Synchronization
 Headset
 Conference Table
 Cordless Computer
 Business Card
Exchange
 Instant Postcard
 Computer
Speakerphone

12. Sharing Common Data…
Usage scenarios:
Synchronization
User benefits
 Proximity synchronization
 Easily maintained database
 Common

13. Wireless Freedom…
Usage scenarios: Headset
User benefits
 Multiple device access
 Cordless phone benefits
 Hand’s free operation

14. PSTN, ISDN,
LAN, WAN, xDSL
Remote Connections...
Usage scenarios: Data access
points
User benefits
 No more connectors
 Easy internet access
 Common connection experience

15. Bluetooth
Specifications

16. Technical Overview

17. Application Framework
and Support
Link Manager and L2CAP
Radio & Baseband
Host Controller
Interface
RF
Baseband
Audio
Link Manager
L2CAP
TCP/IP HID RFCOMM
Applications
Data
What is Bluetooth?
 A hardware/software description
 An application framework

18. RF
Baseband
Audio
Link Manager
L2CAP
Data
Bluetooth Stack
 A hardware/software/protocol description
 An application framework
RFCOMM
SDP
IP
Applications
Single chip with RS-232,
USB, or PC card interface

19. RF
Baseband
Audio
Link Manager
L2CAP
Data
Bluetooth Radio Specification
RFCOMM
SDP
IP
Applications
0 dBm
-20
-70
-91
Tx power
Rx power @ 10 cm
Rx power @ 10m
Noise floor
C/I = 21 dB

20. Power consciousness
 Standby current < 0.3 mA
• 3 months(*)
 Voice mode 8-30 mA
• 75 hours
 Data mode average 5 mA
(0.3-30mA, 20 kbps, 25%)
• 120 hours
 Low-power architecture
• Programmable data length (else radio sleeps)
• Hold and Park modes: 60 µA
 Devices connected but not participating
 Hold retains AMA address, Park releases AMA, gets PMA
address
 Device can participate within 2 ms
(*)Estimates calculated with 600 mAh battery and internal amplifier, power
will vary with implementation

21. Radio
 Low Cost
• Single chip radio (minimize external components)
• Today’s technology
• Time division duplex
 Low Power
• Standby modes
• Sniff, Hold, Park
• Low voltage RF
 Robust Operation
• Fast frequency hopping 1600 hops/sec
• Strong interference protection
 Fast ARQ
 Robust access code
 Forward header correction

22. RF
Baseband
Audio
Link Manager
L2CAP
Data
Baseband
RFCOMM
SDP
IP
Applications

23. Baseband protocol
 Standby
• Waiting to join a
piconet
 Inquire
• Ask about radios to
connect to
 Page
• Connect to a specific
radio
 Connected
• Actively on a piconet
(master or slave)
 Park/Hold
• Low-power connected
states
Inquiry Page
Connected
AMA
Transmit
data
AMA
HOLD
AMA
PARK
PMA
T =2ms
tpcl
Low-power
states
Active
states
Standby
Connecting
states
Unconnected
Standby
T =2ms
tpcl
T =0.6s
tpcl
T =2s
tpcl
releases
AMA address

24. Connection Setup
 Inquiry - scan
protocol
• to lean about the
clock offset and
device address of
other nodes in
proximity

25. Piconet formation
Master
Active Slave
Parked Slave
Standby
 Page - scan
protocol
• to establish links
with nodes in
proximity

26. M
M
S
S
S
S
P
sb
sb
P
P
The Bluetooth network topology
 Radio designation
• Connected radios can be master or slave
• Radios are symmetric (same radio can be
master or slave)
 Piconet
• Master can connect to 7 simultaneous or
200+ active slaves per piconet
• Each piconet has maximum capacity (1
MSps)
• Unique hopping pattern/ID
 Scatternet
• High capacity system
• Minimal impact with up to 10 piconets
within range
• Radios can share piconets!

27. The piconet
IDa
P
M S
or
sb
A
D
C
B
E
IDb
IDa
IDc
IDd
IDe
M
P
S
S
sb
IDa
IDc
IDd
IDa
IDa
IDa
IDe
IDb
 All devices in a piconet hop together
• To form a piconet: master gives slaves its clock and device ID
 Hopping pattern determined by device ID (48-bit)
 Phase in hopping pattern determined by Clock
 Non-piconet devices are in standby
 Piconet Addressing
• Active Member Address (AMA, 3-bits)
• Parked Member Address (PMA, 8-bits)

28. Piconet
 One unit acts as the master of the
Piconet, whereas the others acts as
slaves.
 Up to seven slaves can be active.
 More slaves can be synchronized &
locked to the master in parked state.
 The channel access for all the slaves in
a piconet is controlled by the master.

29. Piconet (2)

30. Scatternet
 Scatternet is formed by multiple Piconets
with overlapping coverage areas.
 Each Piconet can only have a single
master
 Slaves can participate in different
Piconets on a time-division multiplex
basis.
 A master in one Piconet can be a slave in
another Piconet.
 Each Piconet has its own hopping channel
in a Scatternet.

31. Scatternet (2)

32. Addressing
 Bluetooth device address (BD_ADDR)
• 48 bit IEEE MAC address
 Active Member address (AM_ADDR)
• 3 bits active slave address
• all zero broadcast address
 Parked Member address (PM_ADDR)
• 8 bit parked slave address

33. Piconet channel
m
s1
s2
625 sec
f1 f2 f3 f4
1600 hops/sec
f5 f6
FH/TDD

34. Multi slot packets
m
s1
s2
625 sec
f1 f4 f5 f6
FH/TDD
Data rate depends on type of packet

35. Packet Format
Access
code
Header Payload
72 bits 54 bits 0 - 2745 bits
Synchronization
identification
Filtering
Address
Packet Type
Flow control
ARQ
SEQN
HEC
Error correction
1/3 rate FEC
2/3 rate FEC
ARQ scheme for
the data
Smaller than an ATM cell !
Notice that there is no protocol type field

36. Physical Link Types
 Synchronous Connection Oriented (SCO)
Link
• slot reservation at fixed intervals
 No ARQ, No CRC
 FEC (optional)
 64 Kbps
 Asynchronous Connection-less (ACL) Link
• Polling access method
• ARQ, CRC
• FEC (optional)
• Symmetric data rate 108 - 433 Kbps
• Asymmetric data rate up to 723 Kbps

37. Error handling
 Forward-error correction (FEC)
• headers are protected with 1/3 rate FEC and HEC
• payloads may be FEC protected
 1/3 rate: simple bit repetition (SCO packets only)
 2/3 rate: (10,15) shortened Hamming code
 3/3 rate: no FEC
 ARQ (ACL packets only)
• 16-bit CRC (CRC-CCITT) & 1-bit ACK/NACK
• 1-bit sequence number
access code header payload
72b 54b 0-2745b

38. Mixed Link Example
m
s1
s2
SCO SCO SCO
ACL ACL ACL
ACL ACL ACL

39. Inter piconet communication
Cell phone Cordless
headset
Cordles
s
headset
Cell phone
Cordless
headset
Cell phone
mouse

40. Scatternet, scenario
How to schedule presence in
two piconets?
Forwarding delay ?
Missed traffic?

41. RF
Baseband
Audio
Link Manager
L2CAP
Data
Link Manager Protocol
RFCOMM
SDP
IP
Applications Setup and Management
of Baseband connections
• Piconet Management
• Link Configuration
• Security
LMP

42. Link Manager Protocol
 Piconet Management
• Attach and detach slaves
• Master-slave switch
• Establishing SCO and ACL links
• Handling of low power modes ( Sniff, Hold,
Park)
 Link Configuration
• packet type negotiation
• power control
 Security functions
• Authentication
• Encryption

43. Bluetooth security features
 Fast frequency hopping (79 channels)
 Low transmit power (range <= 10m)
 Authentication of remote device
• based on link key (128 Bit)
• May be performed in both directions
 Encryption of payload data
• Stream cipher algorithm ( 128 Bit)
• Affects all traffic on a link
 Initialization
• PIN entry by user

44. KAD
A
B
C
D
M
KMC
KMA
KMD
KMB
Link keys in a piconet
 Link keys are
generated via a PIN
entry
 A different link key
for each pair of
devices is allowed
 Authentication:
• Challenge-Response
Scheme
 Permanent storage
of link keys

45. Key generation and usage
PIN
E2
Link Key
Encryption Key
E3
Encryption
Authentication
PIN
E2
Link Key
Encryption Key
E3
User Input
(Initialization)
(possibly)
Permanent
Storage
Temporary
Storage

46. Application level security
 Builds on-top of link-level security
• creates trusted device groups
 Security levels for services
• authorization required
• authentication required
• encryption required
 Different or higher security requirements
could be added:
• Personal authentication
• Higher security level
• Public key

47. L2CAP
RF
Baseband
Audio
Link Manager
L2CAP
Data
RFCOMM
SDP
IP
Applications Logical Link Control and
Adaptation Protocol
• L2CAP provides
• Protocol multiplexing
• Segmentation and Re-assembly
• Quality of service negotiation
• Group abstraction

48. L2CAP Packet Format (CO)
Length DCID Payload
15 bits 16 bits 0 - 64K bytes
Baseband packets Minimum MTU is 48 bytes !
default is 672 bytes !

49. L2CAP Packet Format (CL)
Length DCID Payload
15 bits 16 bits 0 - 64K bytes
Baseband packets
PSM

50. RF
Baseband
Audio
Link Manager
L2CAP
Data
Serial Port Emulation using
RFCOMM
RFCOMM
SDP
IP
Applications
Serial Port emulation on top of a
packet oriented link
• Similar to HDLC
• For supporting legacy apps

51. RF
Baseband
Audio
Link Manager
L2CAP
Data
Bluetooth Service Discovery
Protocol
RFCOMM
SDP
IP
Applications

52. Usage of SDP
 Establish L2CAP connection to remote
device
 Query for services
• search for specific class of service, or
• browse for services
 Retrieve attributes that detail how to
connect to the service
 Establish a separate (non-SDP) connection
to user the service

53. RF
Baseband
Audio
Link Manager
L2CAP
Data
RFCOMM
SDP
IP
Applications
GOALS
IP over Bluetooth V 1.0
 Internet access using
cell phones
 Connect PDA devices
& laptop computers to
the Internet via LAN
access points

54. LAN access point profile
Security
Authentication
Access control
Efficiency
header and data compression
Auto-configuration
Lower barrier for deployment
Access Point
Baseband
LMP
L2CAP
RFCOMM
PPP
IP

55. Software architecture goals
 Support the target usage scenarios
 Support a variety of hardware
platforms
 Good out of box user experience
• Enable legacy applications
• Utilize existing protocols where
possible

56. L2CAP
OBEX
WAP
Printing
Host Controller Interface
vCard/vCal
WAE
Still Image
Audio
TCP/UDP RFCOMM
TCS
HID
IP
Service Discovery
Bluetooth protocols
PPP

57. Bluetooth protocols
 Host Controller Interface (HCI)
• provides a common interface between the
Bluetooth host and a Bluetooth module
 Interfaces in spec 1.0: USB; UART; RS-232
 Link Layer Control & Adaptation
(L2CAP)
• A simple data link protocol on top of the
baseband
 connection-oriented & connectionless
 protocol multiplexing
 segmentation & reassembly
 QoS flow specification per connection (channel)
 group abstraction

58. Bluetooth protocols
 Service Discovery Protocol (SDP)
• Defines a service record format
 Information about services provided by
attributes
 Attributes composed of an ID (name) and a
value
 IDs may be universally unique identifiers
(UUIDs)
• Defines an inquiry/response protocol for
discovering services
 Searching for and browsing services

59. Bluetooth protocols
 RFCOMM (based on GSM TS07.10)
• emulates a serial-port to support a large base of legacy
(serial-port-based) applications
• allows multiple “ports” over a single physical channel
between two devices
 Telephony Control Protocol Spec (TCS)
• call control (setup & release)
• group management for gateway serving multiple devices
 Legacy protocol reuse
• resuse existing protocols, e.g., IrDA’s OBEX, or WAP for
interacting with applications on phones

60. Interoperability & Profiles
Profiles
Protocols
Applications
 Represents default
solution for a usage
model
 Vertical slice through
the protocol stack
 Basis for
interoperability and
logo requirements
 Each Bluetooth device
supports one or more
profiles

61. Profiles
 Generic Access Profile
• Service Discovery Application Profile
• Serial Port Profile
 Dial-up Networking Profile
 Fax Profile
 Headset Profile
 LAN Access Profile (using PPP)
 Generic Object Exchange Profile
• File Transfer Profile
• Object Push Profile
• Synchronization Profile
• TCS_BIN-based profiles
 Cordless Telephony Profile
 Intercom Profile

62. RFCOMM
ACL SCO
Bluetooth Baseband
LMP
L2CAP
IrOBEX
IrMC
Synchronization profile

63. RFCOMM
ACL SCO
Bluetooth Baseband
LMP
L2CAP
Audio
Stream
AT Commands
Headset profile

64. RFCOMM
ACL SCO
Bluetooth Baseband
LMP
L2CAP
PPP
LAN access point profile

65. Research challenges
Techniques for link
formation
Routing over scatternets
Resource Discovery
Plug-n-play applications
s
s
m
s
s
s
s
m
s
s
m
s
s
s
m
s
cell phone Palmpilot
cable modem
PC
keyboard
mouse
head set
Cordless base
Internet
Will the current solutions for each layer
work in this environment?
cell phone Palmpilot
cable modem
PC
keyboard
mouse
head set
Cordless base
Techniques for
Scatternets Formation

66. What is different in this scenario ?
Dynamic network
Isolated network
Simple devices
Small, multi-hop networks
Connection oriented, low-
power link technology
Applications ---> services ----> routing ----> link creation
cell phone Palmpilot
cable modem
PC
keyboard
mouse
head set
cordless
base
s
s
m
s
s
s
s
m
s
s
m
s
s
s
m
s

67. Service discovery
cell phone Palmpilot
cable modem
PC
keyboard
mouse
head set
cordless
base
s
s
m
s
s
s
s
m
s
s
m
s
s
s
m
s
Need solutions for address allocation,
name resolution, service discovery
Existing solutions in the Internet
depend on infrastructure
Judicious use of Multicast/broadcast
is needed

68. Routing over Scatternets
x7
x8
x6
x4
x3
x5
y2
x2
x1 y1
Nodes must co-operate to forward
packets (MANET style protocols)
Forwarding at Layer 2 or Layer 3?
Bridging or routing ?
What interface should be exported to the above layer?
Better coupling with the service discovery layer is needed

69. Summary
 Bluetooth is a global, RF-based (ISM band:
2.4GHz), short-range, connectivity technology
& solution for portable, personal devices
• it is not just a radio
• create piconets on-the-fly (appr. 1Mbps)
 piconets may overlap in time and space for high aggregate
bandwidth
 The Bluetooth spec comprises
• a HW & SW protocol specification
• usage case scenario profiles and interoperability
requirements
 1999 Discover Magazine Awards finalist
 To learn more: http://www.bluetooth.com