Presentation on theme: "Bluetooth Introduction The Bluetooth Technology"— Presentation transcript:
1 Bluetooth Introduction The Bluetooth Technology Why BluetoothHistoryThe Bluetooth TechnologyThe Bluetooth StackBluetooth in ad hoc networks
2 Introduction Why Bluetooth? Cable replacement between devices. Supported by major companies.Open SpecificationLow power consumptionConnection can be initiated without user interaction.Devices can be connected to multiple devices at the same time.
3 History The technology was born in 1994. The first version was released July 1999.The Bluetooth name comes from the Danish Viking Harald Blåtand.
5 RadioBluetooth devices operate on 2.4 GHz Industrial Scientific Medical band (ISM band).Unlicensed in most countries.Interferences from:Other radio frequency short-range techniquesWireless local area networks (IEEE )Random noise generators (microwave ovens)Other Bluetooth units
6 Radio (cont.) Techniques to minimize packet loss: Frequency Hopping Adaptive power controlShort data packets
7 Frequency Hopping Uses FHSS (Frequency Hopping Spread Spectrum) Divides the ISM-band into 79 1-Mhz channels.Communication between devices switches between available channels.
9 Power ControlThree power classes defined with max output power from 1 mW (Class 1) to 100 mW (Class 3).Devices may be implementet with power controlOptimize power consumptionDecrease interferenceBluetooth provides three types of power classes. These classes provide power and range asfollows:Type Power Level Operating RangeClass 3 Devices 100mW Up to 100 metersClass 2 Devices 10mW Up to 10 metersClass 1 Devices 1mW metersEach has its usage. Class 1 is a cable replacement for a mouse or keyboard. Class 2 is toconnect a laptop to PDA, PDA to PDA, or laptop to laptop. Class 3 can compete with band could be used for all of the above, or it can provide wireless connectivity for a whole building.
11 BasebandResponsible for channel coding/decoding, timing and managing a Bluetooth link.Master/slaveDevices in a connection are either master or slave.Communication is only possible between a master and its slaves.A master and the slaves are named piconets.Scatternet; multiple piconets connected together.
13 The Link ManagerResponsible for establishing, supervising and tear down connections and logical links.Link controller states introduced to carry out these tasks.States:StandbyInquiry / Inquiry ScanPage / Page ScanConnection
14 The Link Manager (cont.) InquiryUsed to detect all devcies in an unknown environment.Page / Page ScanDescribes how connection is established.Have to know the address of the other devices. Is usually achieved through inquiry.ConnectionMaster and slaves are synchronized.Connection is established.
17 Host Controller Interface (HCI) Provided to ease the partition of the Bluetooth Stack across two processors.Some systems will implement the baseband and link manager on the Bluetooth device and higher levels on the host processor.The HCI is provided as an interface between these parts.
18 Logical Link Control and Adaption (L2CAP) Deals withmultiplexing of different servicessegmentationreassembling of packetsQuality of Service
19 ProfilesProvide interoperability between devices from different manufacturers for specific services and use cases.A profile definesa selection of messages and proceduresgives an unambiguous description of communication between two devices.
20 Bluetooth in ad hoc networks Bluetooth network infrastructure is of dynamic ad-hoc type.It is constantly changing and depending on the movement of the devices.
21 Bluetooth in ad hoc networks (cont.) Temporary networks.Connect ”on-the-fly”.Small wireless network called ”personal area network” (PAN).Provide voice, data, eliminate cables, bridge networks.Supports PDAs, mobile phones, printers, faxes, microphones.
22 Bluetooth in ad hoc networks (cont.) The master can support up to 7 devices in its network.Devices use the same frequency, but can be in multiple networks.
23 SecurityBluetooth provides security only over the radio link, from each device to all other devices.Three security specifications:ConfidentialityAuthenticationAuthorization
24 Bluetooth in the future Bluetooth was originally intended to be a cable replacement,but, has evolved to become an infrastructure for Personal Area Network (PAN)2001: 10 million devices produced2003: 70 million!