Sattam Al-Sahli – 237929
Emad Al-Hemyari – 246410
Contents:
o Introduction
• What is Bluetooth?
• The Name –Bluetooth?
o Bluetooth Architecture
• Radio Layer
• Base band Layer
• Link Manager Protocol (LMP)
• Logical Link Control and Adaptation Protocol
• Profiles & Applications Layer
o Operation between Devices
o Operation between Layers
o MATLAB Simulation
o Conclusion
Introduction:
• Bluetooth is a wireless protocol utilizing short-
range communications technology for both voice and
data transmissions over short distances from fixed or
mobile devices, creating wireless personal area
networks (PANs).
• It has been named after Harald Bluetooth who was
the king of Denmark around the turn of the last
millennium.
Bluetooth Architecture
• Bluetooth is both a hardware-based radio system and a
software stack that specifies the linkages between layers. This
supports flexibility in implementation across different devices
and platforms. It also provides robust guidelines for maximum
interoperability and compatibility.
Bluetooth Architecture: Radio Layer
• The Bluetooth Radio (layer) is the lowest defined layer of the
Bluetooth specification.
• The Bluetooth transceiver device operates in the 2.4GHz ISM
band.
• It does the modulation and demodulation of data into RF
signals for transmission in the air.
• The radio layer describes the physical characteristics of the
Bluetooth receiver-transmitter components.
• These include modulation characteristics, radio frequency
tolerance, and sensitivity level.
Bluetooth Architecture: Radio Layer
Transmitter Characteristics
• The Bluetooth radio accomplishes spectrum spreading by
frequency hopping or FDM:
• In 79 hops. In France, a 23-hop system is used.
• Displaced by 1 MHz as a guard band.
• Starting at 2.402GHz and finishing at 2.480GHz.
• Power Classes:
Type Characteristics
Class 1 Long range (~100m) devices, with a max output power of 20 dBm.
Class 2 Ordinary range devices (~10m) devices, with a max output power of 4 dBm.
Class 3 Short range devices (~10cm) devices, with a max output power of 0 dBm.
• The Bluetooth radio module uses Gaussian Frequency Shift Keying.
• Radio Frequency Tolerance of ±75 kHz from the center freq.
Bluetooth Architecture: Radio Layer
Receiver Characteristics
• Sensitivity level for which the BER 0.1% is met in max.
• Out of band blocking is measured with the wanted signal 3dB
over the reference sensitivity level.
• The maximum usable input level at the receiver shall be better
than –20 dBm.
• A Receiver Signal Strength Indicator (RSSI) provides a power-
controlled link that measures its own receiver signal strength
and determine if the transmitter on the other side of the link
should increase or decrease its output power level.
Bluetooth Architecture: Bluetooth Baseband
• Baseband is the physical layer of the Bluetooth.
• It manages physical channels and links apart from other
services like error correction, data whitening, hop selection
and Bluetooth security.
• The Baseband layer lies on top of the Bluetooth radio layer in
the Bluetooth stack.
• The baseband also manages asynchronous and synchronous
links, handles packets and does paging and inquiry to access
and inquire Bluetooth devices in the area.
• The baseband transceiver applies a time-division duplex (TDD)
scheme.
Bluetooth Architecture: Bluetooth Baseband
Physical Characteristics
• The channel is represented by a pseudo-random hopping
sequence hopping through the 79 or 23 RF channels.
• Two or more devices using the same channel form a piconet.
• There is one master and one or more slave(s) in each piconet.
• The hopping sequence is unique for the piconet and is
determined by the Bluetooth device address of the master.
• The channel is divided into time slots where each slot
corresponds to an RF hop frequency , each 625 us in length.
• Consecutive hops correspond to different RF hop frequencies.
• The time slots are numbered according to the Bluetooth clock
of the piconet master.
• TDD scheme is used where master and slave alternatively
transmit.
Bluetooth Architecture: Bluetooth Baseband
Physical Characteristics
o The Baseband handles two types of links:
• SCO (Synchronous Connection-Oriented) link: a symmetric point-to-
point link between a master and a single slave in the piconet, mainly
carries voice information.
• ACL (Asynchronous Connection-Less) link: a point-to-multipoint link
between the master and all the slaves participating on the piconet,
packet retransmission is applied.
o Bluetooth has five logical channels which can be used to
transfer different types of information.
o Data Packet Format: L2CAP is packet-based.
Bluetooth Architecture:
Link Manager Protocol (LMP)
• The Link Manager Protocol (LMP) is used to control and negotiate
all aspects of the operation of the Bluetooth connection between
two devices including setting-up and controlling the:
• logical transports.
• logical links.
• physical links.
• LMP messages are exchanged over the ACL-C logical link that is
carried on the default ACL logical transport.
• The ACL-C logical link is distinguished from the ACL-U (which carries
L2CAP and user data) by the Logical Link Identifier (LLID) field
carried in the payload header of variable-length packets.
• The LMP operates in terms of transactions which are connected set of
message exchanges achieving a particular purpose.
Bluetooth Architecture:
Logical Link Control and Adaptation Protocol
• The Logical Link Control and Adaptation Layer Protocol
(L2CAP) is layered over the Baseband Protocol and resides in
the data link layer.
• L2CAP provides connection-oriented and connectionless data
services to upper layer protocols with:
• protocol multiplexing capability.
• Segmentation.
• reassembly operation.
• group abstractions.
• L2CAP State Machine: L2CAP connection-oriented channel state
machine is described by the following figure.
Bluetooth Architecture: Profiles
• The profiles have been developed in order to describe how
implementations of user models are to be accomplished.
• A profile can be described as a vertical slice through the
protocol stack.
• It defines:
– options in each protocol that are mandatory for the profile.
– And parameter ranges for each protocol.
• The Bluetooth profile structure and the dependencies of the
profiles are depicted in the following figure.
Operation between Devices
• It is represented by the connection-oriented data channels,
where a CID identifies each endpoint of the channel.
• These channels are used to support a channel ’group’ where
the CID on the source represents one or more remote devices.
• There are also a number of CIDs reserved for special
purposes, such as signaling.
• This channel is used to:
– create and establish connection-oriented data channels.
– negotiate changes in the characteristics of these channels.
Operation between Layers
L2CAP implementations follow the general architecture
described here:
• L2CAP implementations must transfer data between higher
layer protocols and the lower layer protocol.
• Each implementation must also support a set of signaling
commands for use between L2CAP implementations.
• L2CAP implementations should also be prepared to accept
certain types of events from lower layers and generate events to
upper layers.
MATLAB Simulation
References
• Palo wireless Bluetooth Resource Center
www.palowireless.com
• Official Bluetooth site aimed at users
www. Bluetooth .com
Questions