Bluetooth Layer Structure

Yong Heui Cho @ Mokwon University

Some of slides are referred to:[1] Victer Paul, Bluetooth, slideshare, 2011.[2] Erin Yueh, Android Bluetooth Introduction, slideshare, 2009.[3] Lawrence Harte, Introduction to Bluetooth, Althos, 2008.

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Smart Device M2M

4. Arduino - Bluetooth Setup

5. Android - Bluetooth Commo6. Bluetooth Layer Structure

7. Arduino - IoT Daisy Chain

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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.

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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.

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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.

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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

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Bluetooth in Android

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Link Manager

□ Courtesy to Lawrence Harte, Introduction to Bluetooth, Althos.

• LM can setup, manage and terminate communication channels between devices. – ACL– SCO– Stream

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Host Controller Interface

□ Courtesy to Lawrence Harte, Introduction to Bluetooth, Althos.

• HCI allows the host stack or controller IC to be swapped with minimal adaptation.

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L2CA• Logical Link Control and

Adaptation• L2CA sets up and controls logical

channel packet with CID.

□ Courtesy to Lawrence Harte, Introduction to Bluetooth, Althos.

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Telephony Control

□ Courtesy to Lawrence Harte, Introduction to Bluetooth, Althos.

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Bluetooth Profiles• Bluetooth profiles are definitions of possible applications

and specify general behaviors that Bluetooth enabled devices use to communicate with other Bluetooth devices.

□ Courtesy to Lawrence Harte, Introduction to Bluetooth, Althos.

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GATT Profiles• GATT: Generic Attribute

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BR/EDR Profiles• BR/EDR: Basic Rate/Enhanced Data

Rate