Sattam Al-Sahli – 237929Sattam Al-Sahli – 237929Emad Al-Hemyari – 246410Emad 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 Deviceso Operation between Layerso MATLAB Simulationo 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 LayerTransmitter 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 CharacteristicsClass 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 LayerReceiver 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.

• 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 BasebandPhysical 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: Bluetooth BasebandPhysical Characteristics

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.

• 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:Logical Link Control and Adaptation Protocol

• 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.

Bluetooth Architecture: Profiles

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 userswww. Bluetooth .com

Questions