Basics Bluetooth Information LMP, L2CAP. RFCOMM.

1. Bluetooth
• Bluetooth is a standardized
protocol for sending and receiving
data via a 2.4GHz wireless link. It’s
a secure protocol, and it’s perfect
for short-range, low-power, low-
cost, wireless transmissions
between electronic devices.
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2. Technical Overview
• Bluetooth operates in the Industrial, Scientific and Medical (ISM) band.
• Operating frequency 2402 MHz to 2480 MHz
• Frequency Hopping Spread spectrum.
Power classes
Class Max output Power dBm Max Range
Class 1 20 dBm 100 m
Class 2 4 dBm 10 m
Class 3 0 dBm Less than 1 m
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3. Bluetooth Name and
address
• Bluetooth device has a unique 48-bit
address (BD_ADDR).
• usually be presented in the form of
• The most-significant half (24 bits) of the
address is an organization unique
identifier (OUI), which identifies the
manufacturer. a 12-digit hexadecimal
value.
• The lower 24-bits are the more unique
part of the address.
• Bluetooth devices can also have user-
friendly names. They can be up to 248
bytes long, and two devices can share
the same name to them.
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4. How Bluetooth Works
• Bluetooth networks (commonly referred to
as piconets) use a master/slave model to control
when and where devices can send data. In this
model, a single master device can be connected
to up to seven different slave devices. Any slave
device in the piconet can only be connected to a
single master.
Connection Process
• Inquiry –
• Paging (Connecting)
• Connection –
o Active Mode - This is the regular connected mode,
where the device is actively transmitting or receiving
data.
o Sniff Mode - It’ll sleep and only listen for
transmissions at a set interval (e.g. every 100ms).
o Hold Mode - where a device sleeps for a defined
period and then returns back to active mode when
that interval has passed.
o Park Mode - A master can command a slave to
“park”, and that slave will become inactive until the
master tells it to wake back up.
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5. Connection Link
Data Links
• ACL links are used to pass application
data and radio-to-radio control messages
from one device to another
• Basic Data Rate ACL links are limited to
approximately 720 KBits/Sec based on a 1
MBit/sec data rate
• Enhanced Data Rate (EDR) ACL links
provide up to 2.16 MBits/Sec based on a
3 Mbit/sec data rate
• The Advanced Audio Distribution Profile
(A2DP) provides for the streaming of high
quality audio over ACL links
Audio Links
• SCO (Synchronous Connection Oriented)
and eSCO (Extended SCO) links are
commonly used for audio transmission
• Audio quality is roughly the same as that
of the public telephone network
• SCO/eSCO links provide guaranteed time
slots
• eSCO links use larger packet sizes than
SCO, allowing more audio information to
be transferred in a single transmission
• This allows eSCO links to also support
retransmission, something that it not
available in SCO
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6. Hopping techniques
Frequency Hopping Spread Spectrum
• Bluetooth uses Frequency Hopping Spread
Spectrum
• Frequency Hopping avoids conflicts with
other devices
• Bluetooth divides the ISM band into 79
channels
• Channel selection is performed such that
all 79 channels are used (approximately)
equally
Adaptive Frequency Hopping (AFH)
• AFH is used to allow Bluetooth to adapt to the
local operating environment
• When using AFH, devices determine channels
that appear to be unreliable
• The devices can then agree not to use the
unreliable channels
• AFH allows Bluetooth to
• Avoid channels where transmission is
unlikely to succeed; improving
throughput since those channels are not
even tried
• Cooperate better with other wireless
technologies by not transmitting on
frequencies that another device is using
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7. BT Communication End to end overview
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8. Description of Stack
Radio –
• Defines power classes
• Frequency bands AFH and channel arrangement.
• Transmitter characteristics. - GFSK Modulation used with
modulation index 0.28
• Receiver characteristics. - BER is equal to 0.1%
Baseband – It is physical layer. Manage Physical characteristics –
1. Physical channels ( use pseudorandom hopping seq)
2. Physical links – ACL and SCO
3. Logical Link – 5 logical link supports by baseband
• LM
• LC – both related to links
• US
• UA
• UI – related to user information
4. Device addressing – BD_ADDR, AM_ADDR
LMP-
Link manager, authentication , error handling.( au_rand,
encrypt_mode, max_slot, host_connection_req.)
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9. HCI –
HCI firmware, HCI drivers, HCI transport layer ( USB, RS232)
L2CAP – Logical link Control and Adaption Protocol
Protocol Multiplexing, Segmentation & Reassembly, Quality of service
The L2CAP Specification is defined for only ACL links and no support for SCO links is
planned.
RFCOMM
RFCOMM is a simple transport protocol, which provides emulation of RS232 serial ports
over the L2CAP protocol. RFCOMM emulates the 9 circuits of an RS-232 interface.
The protocol is based on the ETSI standard TS 07.10. Only a subset of the TS 07.10
standard is used.
SDP
The service discovery protocol (SDP) provides a means for applications to discover which
services are available and to determine the characteristics of those available services.

10. Bluetooth Modules
• Bluetooth Module
• Murata’s Wi-Fi™ and Bluetooth®
combination modules are IEEE 802.11
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11. BT Air Traces using BPA 600
• In Band Ringtone
• AVRCP Version
• Browsing
• Repeat and shuffle
• Calling
• Sim contacts
• Role switch
Frames need to discuss
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12. Trace for reference
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13. Player Application settings
Traces of Nokia 8 with Clarion System Traces of Nokia 8 with Uconnect
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