Introduction to Bluetooth
17
Introduction to Bluetooth Yong Heui Cho @ Mokwon University Most of slides are referred to and all credits should go to: [1] Victer Paul, Bluetooth, slideshare, 2011. [2] Erin Yueh, Android Bluetooth Introduction, slideshare, 2009.
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Transcript of Introduction to Bluetooth
Introduction to Bluetooth
Yong Heui Cho @ Mokwon University
Most of slides are referred to and all credits should go to:[1] Victer Paul, Bluetooth, slideshare, 2011.[2] Erin Yueh, Android Bluetooth Introduction, slideshare, 2009.
2
Smart Device Structure
8. Introduction to IoT
9. Smart Device RF & Anten-nas10. Introduction to RTOS
11. Introduction to Bluetooth
3
Why Bluetooth?• Aims at so-called ad hoc piconets
which are local area networks with a very limited coverage and without the need for an infrastructure.
• Designed to be used to connect both mobile devices and peripherals that currently require a wire
□ Courtesy to Victer Paul, Bluetooth, slideshare.
4
Spec. (I)• “USB without wires”• Short range wireless radio
technology–Operation range of 10 meters– RF is centered at 2.45 GHz. (RF
Channels: 2420+k MHz, k = 0~78)– Frequency hopping is used to combat
interference in wireless environment.– TDD for full duplex communications
□ Courtesy to Victer Paul, Bluetooth, slideshare.
5
Spec. (II)• Power levels– Sleeping power - 30 uA– Transmission power - 800 uA– Standby mode - 300 uA
• Price is less.• Operates on circuit and packet
switching modes• Provides both asynchronous and
synchronous data services.□ Courtesy to Victer Paul, Bluetooth, slideshare.
6
Spec. (III)• Compared to wired and wireless
LAN(10 Mbps), Bluetooth is slower.
• Bluetooth can – Recognize Bluetooth device in radio
range.– Permit easy connection of devices.– Be aware of device types.– Support service discovery.
□ Courtesy to Victer Paul, Bluetooth, slideshare.
7
Possible Devices• Bluetooth will soon be enabled in
everything from:– Smartphones–Headsets – Computers– Cameras– Smart devices– Cars– etc.
□ Courtesy to Victer Paul, Bluetooth, slideshare.
8
Radio Coverage• Class 3 radios – have a range of
up to 1 meter or 3 feet• Class 2 radios – most commonly
found in mobile devices – have a range of 10 meters or 30 feet
• Class 1 radios – used primarily in industrial use cases – have a range of 100 meters or 300 feet
□ Courtesy to Victer Paul, Bluetooth, slideshare.
9
Overview• Capacity– 1 Mbps per channel– Theoretical capacity of 79 Mbps cannot
be reached due to non-orthogonal hopping sequences
• Link types– Synchronous connection-oriented link
(SCO)– Asynchronous connectionless link (ACL)
• Topology and medium access control– Master-slave architecture
□ Courtesy to Victer Paul, Bluetooth, slideshare.
10
Link Types• SCO (Synchronous Connection-Oriented)
– The SCO link is point-to-point between master and slave. The master maintains the link by using reserved timeslots at regular intervals. Packet retransmissions are not allowed.
• ACL (Asynchronous Connection-Less)– ACL provides packet-switched connections
between the master and all active slaves. Packet retransmissions are usually applied to assure data integrity.
□ Courtesy to Victer Paul, Bluetooth, slideshare.
11
Power States
□ Courtesy to Victer Paul, Bluetooth, slideshare.
low power mode
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Power Management• Stand-by (SB) or idle
– Devices not connected in a piconet– Extremely low duty cycle (less than one percent): scan for 10
ms every 1.28-3.84 seconds• Park (P)
– Devices are part of a piconet, but not active, low power mode– Assigned an 8-bit parked member address (PMA) and loses
active member address (AMA).• Hold (H)
– Similar to parked mode, but devices keep AMA address– Resume sending at once after transition out of HOLD state
• Sniff (Sn)– Used only by slave devices for power conservation– Device is active, but listens to channel at a reduced rate. Not
on every slot
□ Courtesy to Victer Paul, Bluetooth, slideshare.
13
Piconet
□ Courtesy to Victer Paul, Bluetooth, slideshare.
14
Scatternet
□ Courtesy to Victer Paul, Bluetooth, slideshare.
15
Protocol Stack
□ Courtesy to Victer Paul, Bluetooth, slideshare.
• OBEX: Object Exchange• RFCOMM: RF Communication • SDP: Service Discovery Protocol• TCS: Telephony Control Protocol• WAP: Wireless Application Protocol
16
Android Bluetooth
□ Courtesy to Erin Yueh, Android Bluetooth Introduction, slideshare.
17
Bluetooth Architecture
□ Courtesy to Erin Yueh, Android Bluetooth Introduction, slideshare.
