This document summarizes the Bluetooth layer structure. It discusses the link types in Bluetooth including SCO and ACL links. It also outlines the Bluetooth protocol stack including layers like L2CAP, RFCOMM, and SDP. Finally, it briefly explains Bluetooth profiles and how GATT and BR/EDR profiles define possible applications.

1. 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.

2. 2
Smart Device M2M
4. Arduino - Bluetooth Setup
5. Android - Bluetooth Commo
6. Bluetooth Layer Structure
7. Arduino - IoT Daisy Chain

3. 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. 4
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.

5. 5
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.

6. 6
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

7. 7
Bluetooth in Android

8. 8
Link Manager
□ Courtesy to Lawrence Harte, Introduction to Bluetooth, Althos.
• LM can setup,
manage and
terminate
communication
channels between
devices.
– ACL
– SCO
– Stream

9. 9
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.

10. 10
L2CA
• Logical Link Control and Adaptation
• L2CA sets up and controls logical
channel packet with CID.
□ Courtesy to Lawrence Harte, Introduction to Bluetooth, Althos.

11. 11
Telephony Control
□ Courtesy to Lawrence Harte, Introduction to Bluetooth, Althos.

12. 12
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.

13. 13
GATT Profiles
• GATT: Generic Attribute

14. 14
BR/EDR Profiles
• BR/EDR: Basic Rate/Enhanced Data Rate