Bluetooth Introduction and Architecture

1. Presented by
Ms.M.Vaishnavi
AP/ECE
KIT-Kalaignarkarunanidhi Institute of
Technology
1

2. 2

3.  Cable replacement technology.
› It Connects devices such as phone
handsets, headsets, computer peripherals,
etc.
 Industry standard.
› Allows wireless communication between
devices.
3

4.  1 Mb/s.
 Range ~10 meters.
 PANs
 Single chip radio.
› Low power & low cost.
4

5.  Multiple device
access.
 Hands-free
operation.
5
Cordless
headset

6.  Conference table.
 Cordless computer.
 Instant photo transmission.
 Cordless phone.
6

7.  Recently, IEEE 803.15.1 standard for
Wireless PANs (WPANs)
› Only MAC and PHY.
 Open spec.
 Low cost.
 Power efficiency.
 Lightweight and small form factor.
 Reliable and resilient to failures.
7

8.  Defines a protocol stack to enable
heterogeneous devices to
communicate.
 The Bluetooth stack includes protocols
for the radio layer all the way up to
device discovery, service discovery, etc.
8

9. 9
RF
Baseband
Link Manager
L2CAP
RFCOMM/SDP
Applications
Link Controller
Host Controller Interface
PHY
Data Link Layer
Network Layer
Transport Layer
Session Layer
Presentation Layer
Application
OSI/ISO

10.  Radio: physically transmits/receives data.
 Baseband/Link Controller: controls PHY.
 Link Manager: controls links to other
devices.
 Host Controller:e2e communication.
 Logical Link Control:
multiplexes/demultiplexes data from higher
layers.
 RFCOMM: RS323-like serial interface.
 SDP: allows service discovery among
Bluetooth devices.
10

11.  2.4 GHz license-free ISM band.
 Available worldwide.
 Industrial, Scientific, Medical (ISM) band.
› Unlicensed, globally available.
› Centered around 2.4 GHz.
 Resilient to interference.
 Frequency hopping.
 Range: 10, 20, and 100m.
 1MB/s.
11

12. 12
Carries out MAC
functions.
RF
Baseband
Link Manager
L2CAP
RFCOMM/SDP
Applications
Link Controller
Host Controller Interface
Control end of baseband
+link controller=
Data link layer

13.  Communicating devices must agree on
hopping sequence.
 BT devices can operate as masters or
slaves.
 Master node defines sequence to be used.
 Slave units use master id to pick sequence.
 Master also controls when devices are
allowed to transmit.
› Master allocates slots to slaves.
› Allocates total available bandwidth among
slaves.
13

14.  BT communication takes place over piconets.
 Piconet formation initiated by master and all
other participants are slaves.
 Number of participants limited to 8.
 Master/slave roles last for the duration of the
piconet.
 On a piconet, slaves only have direct links to
master.
 Point-to-point or point-to-multipoint
connections.
14

15. 15
Standby
Inquiry Page
Transmit Connected
Park Hold Sniff
Unconnected
Connectin
g
Active
Low power
. Initially, all nodes in
standby.
. Node (master) can begin
inquiry to find nearby
devices.
. Piconet is then formed.
. Devices join by paging.

16. 16
• Device discovery
• Listeners respond with
their address.

17. 17
Master
Active Slave
Parked Slave
Standby
• Device enters paging to
invite others to join its
piconet.
• Establishes links with nodes
in proximity.
• Paging message unicast to
selected receiver.
• Receiver sends ACK.
• Sender becomes master,
receiver slave.

18.  Master can actively try to discover new
nodes or wait (in scan/listen mode) to be
discovered.
 Communication in the current piconet
suspended.
 Admission latency versus piconet
capacity tradeoff.
18

19.  Point-to-point link:
› Master-slave relationship.
19
m s
s
s
m
s
• Piconet:
– 8 units: channel capacity.
– Master (establishes piconet) can
connect to up to 7 slaves.
– Master/slave relationship lasts while
link/piconet lasts.
– No slave-to-slave communication.

20.  2 types of links:
› Synchronous (SCO) links:
 Point-to-point between master and slave.
 Link established by reserving slots in either direction
periodically.
 Used to carry real-time traffic (voice).
› Asynchronous (ACL) links:
 Point-to-multipoint between master and slaves.
 Use remaining slots on channel.
 Traffic scheduled by master.
20

21. 21
72 bits 54 bits 0 - 2744 bits
Access
code
Header Payload
DataVoice CRC
No CRC
No retries
625 µs
master
slave
header
ARQ
FEC (optional)
FEC (optional)

22.  Address of piconet
master.
22
Access
code
Header Payload
72 bits

23.  Addressing (3)
 Packet type (4)
 Flow control (1)
 1-bit ARQ (1)
 Sequencing (1)
 HEC (8)
23
Access
code
Header Payload
54 bits
Purpose
Broadcast packets are not ACKed
For filtering retransmitted packets
18 bitstotal
s
s
m
s
16 packet types (some unused)
Max 7 active slaves
Verify header integrity

24.  Piconets may overlap in space and time.
 They can work independently.
› Each with its own hopping sequence.
› Packets with different access codes.
 Or they can overlap, i.e., nodes can
participate in more than 1 piconet.
› “Time sharing”.
24

25.  Interconnection of multiple piconets.
25
Master
Slave

26.  Interconnection by bridge nodes.
› Bridge nodes are members of piconets they
interconnect.
› Bridge node “stay” in a piconet for some
time, then switch to another piconet by
changing hop sequence.
› Do this for all member piconets.
› Send and receive in each piconet.
› Forward from one piconet to another.
26

27. 27
RF
Baseband
Link Manager
L2CAP
RFCOMM/SDP
Applications
Link Controller
Host Controller Interface
Carries out inquiry and paging
operations; manages multiple
links and different piconets.
Attaching/detaching slaves from
piconet; power management; security.

28.  Low-power modes: prolong battery life.
› Devices can be turned-off when idle.
› Devices wake up periodically to
send/receive data.
 Authentication and encryption.
 LMP provides mechanisms for
negotiation of encryption modes, keys,
etc.
28

29. 29
RF
Baseband
Link Manager
L2CAP
RFCOMM/SDP
Applications
Link Controller
Host Controller Interface
Optional interface layer
between higher and lower
layers of the BT stack.
E.g., when lower- and higher
BT layers run on different
Devices: PCMCIA card and
PC’s processor.

30. 30
Logical Link Control and
Adaptation Protocol=
Session Layer.
L2CAP provides
• Protocol multiplexing
• Quality of service negotiationRF
Baseband
Link Manager
L2CAP
RFCOMM/SDP
Applications
Link Controller
Host Controller Interface

31. 31
RF
Baseband
Link Manager
L2CAP
RFCOMM/SDP
Applications
Link Controller
Host Controller InterfaceService discovery, serial port
interface.

32. 32
Features Cost
20 dBm (~100 m)
Point-to-multipoint
No Scatternet
Applications
File Transfer,
Dial-Up Networking
LAN access, Fax, …
169 $
---
200 $
0 dBm (~10 m)
Point-to-multipoint
No Scatternet
File Transfer,
Dial-Up Networking
LAN access, Fax, …
169 $
---
Company
Toshiba,
Motorola,
Digianswer
IBM, TDK
3COM
10 m user-user;
100 m user-Base Station
Point-to-multipoint
SW- & FW-upgradeable
File Transfer,
Dial-Up Networking
LAN access, Fax, E-mail
Unconscious connection
149 $
Nokia
10 m user-user;
Point-to-point
Connectivity Battery
for the cell phone
File Transfer,
Dial-Up Networking
LAN access, Fax, E-mail
Unconscious connection
149 $
Ericsson,
Sigma
10 m user-user;
Point-to-point;
ARM processor;
USB; RFCOMM ports
Basic BT Radio stack
Embedded or Host stack
Programmable
500 $
1500$