1. CSE 4215/5431: Mobile Communications Winter 2010
Suprakash Datta
Office: CSEB 3043
Phone: ext 77875
Course page:
Some slides are adapted from the book website
11/19/2018
CSE 4215, Winter 2010

2. Today
Bluetooth Intro (Ch 7.5)
11/19/2018
CSE 4215, Winter 2010

3. Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
Bluetooth
Basic idea
Universal radio interface for ad-hoc wireless connectivity
Interconnecting computer and peripherals, handheld devices, PDAs, cell phones – replacement of IrDA
Embedded in other devices, goal: 5€/device (already < 1€)
One of the first modules (Ericsson).
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 3

4. Bluetooth - contd Available globally for unlicensed users
Devices within 10 m can share up to 720 kbps of capacity
Supports open-ended list of applications
Data, audio, graphics, video
11/19/2018
CSE 4215, Winter 2010

5. Applications Data and voice access points Cable replacement
Real-time voice and data transmissions
Cable replacement
Eliminates need for numerous cable attachments for connection
Ad hoc networking
Device with Bluetooth radio can establish connection with another when in range
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CSE 4215, Winter 2010

6. Bluetooth - history History Special Interest Group
1994: Ericsson (Mattison/Haartsen), “MC-link” project
Renaming of the project: Bluetooth according to Harald “Blåtand” Gormsen [son of Gorm], King of Denmark in the 10th century
1998: foundation of Bluetooth SIG,
2001: first consumer products for mass market, spec. version 1.1 released
2005: 5 million chips/week
Special Interest Group
Original founding members: Ericsson, Intel, IBM, Nokia, Toshiba
Added promoters: 3Com, Agere (was: Lucent), Microsoft, Motorola
> members
Common specification and certification of products
11/19/2018
CSE 4215, Winter 2010

7. Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
History and hi-tech…
1999:
Ericsson mobile communications AB reste denna sten till minne av Harald Blåtand, som fick ge sitt namn åt en ny teknologi för trådlös, mobil kommunikation.
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 7

8. …and the real rune stone
Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
…and the real rune stone
Located in Jelling, Denmark,
erected by King Harald “Blåtand”
in memory of his parents.
The stone has three sides – one side
showing a picture of Christ.
Inscription:
"Harald king executes these sepulchral monuments after Gorm, his father and Thyra, his mother. The Harald who won the whole of Denmark and Norway and turned the Danes to Christianity."
This could be the “original” colors of the stone.
Inscription:
“auk tani karthi kristna” (and made the Danes Christians)
Blåtand means “of dark complexion”
(not having a blue tooth…)
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 8

9. Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
Characteristics
2.4 GHz ISM band, 79 (23) RF channels, 1 MHz carrier spacing
Channel 0: 2402 MHz … channel 78: 2480 MHz
G-FSK modulation, mW transmit power
FHSS and TDD
Frequency hopping with 1600 hops/s
Hopping sequence in a pseudo random fashion, determined by a master
Time division duplex for send/receive separation
Voice link – SCO (Synchronous Connection Oriented)
FEC (forward error correction), no retransmission, 64 kbit/s duplex, point-to-point, circuit switched
Data link – ACL (Asynchronous Connection Less)
Asynchronous, fast acknowledge, point-to-multipoint, up to kbit/s symmetric or 723.2/57.6 kbit/s asymmetric, packet switched
Topology
Overlapping piconets (stars) forming a scatternet
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 9

10. Standards Documents Core specifications Profile specifications
Details of various layers of Bluetooth protocol architecture
Profile specifications
Use of Bluetooth technology to support various applications
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CSE 4215, Winter 2010

11. Protocol Architecture
Bluetooth is a layered protocol architecture
Core protocols
Cable replacement and telephony control protocols
Adopted protocols
Radio
Baseband
Link manager protocol (LMP)
Logical link control and adaptation protocol (L2CAP)
Service discovery protocol (SDP)
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CSE 4215, Winter 2010

12. Protocol Architecture
Cable replacement protocol
RFCOMM
Telephony control protocol
Telephony control specification – binary (TCS BIN)
Adopted protocols
PPP
TCP/UDP/IP
OBEX
WAE/WAP
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CSE 4215, Winter 2010

13. Usage Models File transfer Internet bridge LAN access Synchronization
Three-in-one phone
Headset
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CSE 4215, Winter 2010

14. Piconets and Scatternets
Basic unit of Bluetooth networking
Master and one to seven slave devices
Master determines channel and phase
Scatternet
Device in one piconet may exist as master or slave in another piconet
Allows many devices to share same area
Makes efficient use of bandwidth
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CSE 4215, Winter 2010

15. Piconet Collection of devices connected in an ad hoc fashion
Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
Piconet
Collection of devices connected in an ad hoc fashion
One unit acts as master and the others as slaves for the lifetime of the piconet
Master determines hopping pattern, slaves have to synchronize
Each piconet has a unique hopping pattern
Participation in a piconet = synchronization to hopping sequence
Each piconet has one master and up to 7 simultaneous slaves (> 200 could be parked) P S S M P SB S P SB
M=Master
S=Slave
P=Parked
SB=Standby
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 15

16. Forming a piconet                  
Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
Forming a piconet
All devices in a piconet hop together
Master gives slaves its clock and device ID
Hopping pattern: determined by device ID (48 bit, unique worldwide)
Phase in hopping pattern determined by clock
Addressing
Active Member Address (AMA, 3 bit)
Parked Member Address (PMA, 8 bit)   P  S   SB SB S    M P SB     SB SB SB S     SB P SB SB   SB SB
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 16

17. Radio Specification Classes of transmitters
Class 1: Outputs 100 mW for maximum range
Power control mandatory
Provides greatest distance
Class 2: Outputs 2.4 mW at maximum
Power control optional
Class 3: Nominal output is 1 mW
Lowest power
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CSE 4215, Winter 2010

18. Frequency Hopping in Bluetooth
Provides resistance to interference and multipath effects
Provides a form of multiple access among co-located devices in different piconets
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CSE 4215, Winter 2010

19. Frequency Hopping Total bandwidth divided into 1MHz physical channels
FH occurs by jumping from one channel to another in pseudorandom sequence
Hopping sequence shared with all devices on piconet
Piconet access:
Bluetooth devices use time division duplex (TDD)
Access technique is TDMA
FH-TDD-TDMA
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CSE 4215, Winter 2010

20. Frequency selection during data transmission
Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
Frequency selection during data transmission
625 µs fk
fk+1
fk+2
fk+3
fk+4
fk+5
fk+6 M S M S M S M t fk
fk+3
fk+4
fk+5
fk+6 M S M S M t fk
fk+1
fk+6 M S M t
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 20

21. Physical Links between Master and Slave
Synchronous connection oriented (SCO)
Allocates fixed bandwidth between point-to-point connection of master and slave
Master maintains link using reserved slots
Master can support three simultaneous links
Asynchronous connectionless (ACL)
Point-to-multipoint link between master and all slaves
Only single ACL link can exist
11/19/2018
CSE 4215, Winter 2010

22. Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
Scatternet
Linking of multiple co-located piconets through the sharing of common master or slave devices
Devices can be slave in one piconet and master of another
Communication between piconets
Devices jumping back and forth between the piconets
Piconets
(each with a
capacity of
720 kbit/s) P S S S P P M M SB S
M=Master
S=Slave
P=Parked
SB=Standby P SB SB S
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 22

23. Bluetooth protocol stack
Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
Bluetooth protocol stack
audio apps.
NW apps.
vCal/vCard
telephony apps.
mgmnt. apps.
TCP/UDP
OBEX
AT modem
commands
TCS BIN
SDP
Control IP
BNEP
PPP
Audio
RFCOMM (serial line interface)
Logical Link Control and Adaptation Protocol (L2CAP)
Host
Controller
Interface
Link Manager
Baseband
Radio
AT: attention sequence
OBEX: object exchange
TCS BIN: telephony control protocol specification – binary
BNEP: Bluetooth network encapsulation protocol
SDP: service discovery protocol
RFCOMM: radio frequency comm.
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 23

24. Bluetooth Packet Fields
Access code – used for timing synchronization, offset compensation, paging, and inquiry
Header – used to identify packet type and carry protocol control information
Payload – contains user voice or data and payload header, if present
11/19/2018
CSE 4215, Winter 2010

25. Types of Access Codes Channel access code (CAC) – identifies a piconet
Device access code (DAC) – used for paging and subsequent responses
Inquiry access code (IAC) – used for inquiry purposes
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CSE 4215, Winter 2010

26. Access Code Preamble – used for DC compensation
0101 if LSB of sync word is 0
1010 if LSB of synch word is 1
Sync word – 64-bits, derived from:
7-bit Barker sequence
Lower address part (LAP)
Pseudonoise (PN) sequence
Trailer
0101 if MSB of sync word is 1
1010 if MSB of sync word is 0
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CSE 4215, Winter 2010

27. Packet Header Fields
AM_ADDR – contains “active mode” address of one of the slaves
Type – identifies type of packet
Flow – 1-bit flow control
ARQN – 1-bit acknowledgment
SEQN – 1-bit sequential numbering schemes
Header error control (HEC) – 8-bit error detection code
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CSE 4215, Winter 2010

28. Payload Format Payload header Payload body – contains user data
L_CH field – identifies logical channel
Flow field – used to control flow at L2CAP level
Length field – number of bytes of data
Payload body – contains user data
CRC – 16-bit CRC code
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CSE 4215, Winter 2010

29. Baseband link types Polling-based TDD packet transmission
Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
Baseband link types
Polling-based TDD packet transmission
625µs slots, master polls slaves
SCO (Synchronous Connection Oriented) – Voice
Periodic single slot packet assignment, 64 kbit/s full-duplex, point-to-point
ACL (Asynchronous ConnectionLess) – Data
Variable packet size (1, 3, 5 slots), asymmetric bandwidth, point-to-multipoint
SCO
ACL
SCO
ACL
SCO
ACL
SCO
ACL
MASTER f0 f4 f6 f8
f12
f14
f18
f20
SLAVE 1 f1 f7 f9
f13
f19
SLAVE 2 f5
f17
f21
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 29

30. Error Correction Schemes
1/3 rate FEC (forward error correction)
Used on 18-bit packet header, voice field in HV1 packet
2/3 rate FEC
Used in DM packets, data fields of DV packet, FHS packet and HV2 packet
ARQ
Used with DM and DH packets
11/19/2018
CSE 4215, Winter 2010

31. ARQ Scheme Elements
Error detection – destination detects errors, discards packets
Positive acknowledgment – destination returns positive acknowledgment
Retransmission after timeout – source retransmits if packet unacknowledged
Negative acknowledgment and retransmission – destination returns negative acknowledgement for packets with errors, source retransmits
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CSE 4215, Winter 2010

32. Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
Robustness
Slow frequency hopping with hopping patterns determined by a master
Protection from interference on certain frequencies
Separation from other piconets (FH-CDMA)
Retransmission
ACL only, very fast
Forward Error Correction
SCO and ACL
Error in payload
(not header!)
NAK
ACK
MASTER A C C F H
SLAVE 1 B D E
SLAVE 2 G G
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 32

33. Baseband states of a Bluetooth device
Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
Baseband states of a Bluetooth device
standby
unconnected
inquiry
page
connecting
detach
transmit
AMA
connected
AMA
active
park
PMA
hold
AMA
sniff
AMA
low power
Standby: do nothing
Inquire: search for other devices
Page: connect to a specific device
Connected: participate in a piconet
Park: release AMA, get PMA
Sniff: listen periodically, not each slot
Hold: stop ACL, SCO still possible, possibly participate in another piconet
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 33

34. Power consumption/CSR BlueCore2
Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
Power consumption/CSR BlueCore2
Typical Average Current Consumption1
VDD=1.8V Temperature = 20°C
Mode
SCO connection HV3 (1s interval Sniff Mode) (Slave) mA
SCO connection HV3 (1s interval Sniff Mode) (Master) 26.0 mA
SCO connection HV1 (Slave) mA
SCO connection HV1 (Master) mA
ACL data transfer 115.2kbps UART (Master) mA
ACL data transfer 720kbps USB (Slave) mA
ACL data transfer 720kbps USB (Master) mA
ACL connection, Sniff Mode 40ms interval, 38.4kbps UART 4.0 mA
ACL connection, Sniff Mode 1.28s interval, 38.4kbps UART 0.5 mA
Parked Slave, 1.28s beacon interval, 38.4kbps UART 0.6 mA
Standby Mode (Connected to host, no RF activity) 47.0 µA
Deep Sleep Mode µA
Notes:
1 Current consumption is the sum of both BC212015A and the flash.
2 Current consumption is for the BC212015A device only.
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 34

35. Example: Bluetooth/USB adapter
Freie Universität Berlin
Institut of Computer Science
Mobile Communications
2002
Example: Bluetooth/USB adapter
11/19/2018
CSE 4215, Winter 2010
Prof. Dr.-Ing. Jochen Schiller 35

36. Logical Channels Link control (LC) Link manager (LM)
User asynchronous (UA)
User isochronous (UI)
User synchronous (US)
11/19/2018
CSE 4215, Winter 2010