Week 6 lecture 1+2Week 6 lecture 1+2Bluetooth

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Finish Data Link layer Finish Data Link layer - CRC- CRC - CSMA- CSMA

- Hints for Lab 4- Hints for Lab 4

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WPAN: WPAN: INTRODUCTIONINTRODUCTION

A WPAN (Wireless PAN) is a short-distance wireless A WPAN (Wireless PAN) is a short-distance wireless network specifically designed to support portable network specifically designed to support portable and mobile computing devices such as and mobile computing devices such as PCs, PDAs, PCs, PDAs, wireless printers and storage devices, cell phones, wireless printers and storage devices, cell phones, pagers, set-top boxes, and a variety of consumer pagers, set-top boxes, and a variety of consumer electronicselectronics equipment. equipment.

BluetoothBluetooth is an example of a wireless PAN that is an example of a wireless PAN that

allows devices within close proximity to join allows devices within close proximity to join together in together in ad hoc wireless networksad hoc wireless networks in order to in order to exchange information.exchange information.

Many cell phonesMany cell phones have two radio interfaces-one for have two radio interfaces-one for

the the cellular networkcellular network and one for and one for PAN PAN connections.connections.

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IEEE 802.15 WPANIEEE 802.15 WPAN

Development of standards for Development of standards for short distanceshort distance wireless networks used for networking of portable wireless networks used for networking of portable ad mobile computing devices.ad mobile computing devices.

The original functional requirement was published The original functional requirement was published in in January 22, 1998January 22, 1998, and specified devices with:, and specified devices with:– Power management: low current consumptionPower management: low current consumption– Range: Range: 0 - 10 meters0 - 10 meters– Speed: Speed: 19.2 - 100 kbps19.2 - 100 kbps– Small size: 0.5 cubic inches without antennaSmall size: 0.5 cubic inches without antenna– Low cost relative to target deviceLow cost relative to target device– Should Should allow overlap of multiple networksallow overlap of multiple networks in the in the

same areasame area– Networking support for a minimum of 16 devicesNetworking support for a minimum of 16 devices

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IEEE 802.15 WPANIEEE 802.15 WPAN

The initial activities in the WPAN group included The initial activities in the WPAN group included HomeRF and Bluetooth group.HomeRF and Bluetooth group.

HomeRF currently has its own website [HomeRFweb]HomeRF currently has its own website [HomeRFweb] IEEE 802.15IEEE 802.15 WPAN has 4 task groups: WPAN has 4 task groups:

– Task group 1: based on BluetoothTask group 1: based on Bluetooth. Defines PHY and . Defines PHY and MAC for wireless connectivity with fixed, portable, MAC for wireless connectivity with fixed, portable, and moving devices within or entering a personal and moving devices within or entering a personal operating space.operating space.

– Task group 2: focused on Task group 2: focused on coexistence of WPAN and coexistence of WPAN and 802.11 WLANs.802.11 WLANs.

– Task group 3: PHY and MAC layers for Task group 3: PHY and MAC layers for high-rate high-rate WPANs (higher than 20 Mbps) -- Not bluetooth!WPANs (higher than 20 Mbps) -- Not bluetooth!

– Task group 4: Task group 4: ultra-low complexity, ultra-low power ultra-low complexity, ultra-low power consuming, ultra-low cost PHY and MAC layer for consuming, ultra-low cost PHY and MAC layer for data rates of up to 200 kbps (such as WSN).data rates of up to 200 kbps (such as WSN).

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WPAN: IEEE 802.15.WPAN: IEEE 802.15.11 – Bluetooth– Bluetooth

Data rateData rate– Synchronous, connection-oriented: Synchronous, connection-oriented:

64 kbit/s64 kbit/s– Asynchronous, connectionlessAsynchronous, connectionless

433.9 kbit/s symmetric433.9 kbit/s symmetric 723.2 / 57.6 kbit/s asymmetric723.2 / 57.6 kbit/s asymmetric

Transmission rangeTransmission range– POS (Personal Operating Space) POS (Personal Operating Space)

up to up to 10 m10 m– with special transceivers up to 100 with special transceivers up to 100

mm FrequencyFrequency

– Free 2.4 GHz ISM-bandFree 2.4 GHz ISM-band SecuritySecurity

– Challenge/response (SAFER+), Challenge/response (SAFER+), hopping sequencehopping sequence

CostCost– 50€ adapter, drop to 5€ if 50€ adapter, drop to 5€ if

integratedintegrated AvailabilityAvailability

– Integrated into some products, Integrated into some products, several vendorsseveral vendors

Connection set-up timeConnection set-up time– Depends on power-modeDepends on power-mode– Max. 2.56s, avg. 0.64sMax. 2.56s, avg. 0.64s

Quality of ServiceQuality of Service– Guarantees, ARQ/FECGuarantees, ARQ/FEC

ManageabilityManageability– Public/private keys needed, key Public/private keys needed, key

management not specified, management not specified, simple system integrationsimple system integration

Special Special Advantages/DisadvantagesAdvantages/Disadvantages

– Advantage:Advantage: already integrated already integrated into several products, available into several products, available worldwide, free ISM-band, worldwide, free ISM-band, several vendors, simple system, several vendors, simple system, simple ad-hoc networking, peer simple ad-hoc networking, peer to peer, scatternetsto peer, scatternets

– Disadvantage:Disadvantage: interference on interference on ISM-band, limited range, max. 8 ISM-band, limited range, max. 8 devices/network&master, high devices/network&master, high set-up latencyset-up latency

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WPAN: IEEE 802.15.2 &3WPAN: IEEE 802.15.2 &3

802.15-2: Coexistence802.15-2: Coexistence– CoexistenceCoexistence of Wireless Personal Area Networks of Wireless Personal Area Networks

(802.15) and Wireless Local Area Networks (802.11), (802.15) and Wireless Local Area Networks (802.11), quantify the mutual interference quantify the mutual interference

802.15-3: High-Rate802.15-3: High-Rate– Standard for high-rate (20Mbit/s or greater) WPANs, Standard for high-rate (20Mbit/s or greater) WPANs,

while while still low-power/low-coststill low-power/low-cost – Data Rates: 11, 22, 33, 44, 55 Mbit/s Data Rates: 11, 22, 33, 44, 55 Mbit/s – Quality of Service isochronous protocol Quality of Service isochronous protocol – Ad hoc peer-to-peer networking Ad hoc peer-to-peer networking – Security Security – Low power consumption Low power consumption – Low cost Low cost – Designed to meet the demanding requirements of Designed to meet the demanding requirements of

portable consumer imaging and multimedia applicationsportable consumer imaging and multimedia applications

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WPAN: IEEE 802.15.4WPAN: IEEE 802.15.4 802.15-4: Low-Rate, Very Low-Power802.15-4: Low-Rate, Very Low-Power

– Low data rate solution with multi-month to multi-year battery life and Low data rate solution with multi-month to multi-year battery life and very low complexityvery low complexity

– Potential applications are sensors, interactive toys, smart badges, Potential applications are sensors, interactive toys, smart badges, remote controls, and home automationremote controls, and home automation

– Data rates of 20-250 kbit/s, latency down to 15 msData rates of 20-250 kbit/s, latency down to 15 ms – Master-Slave or Peer-to-Peer operationMaster-Slave or Peer-to-Peer operation– Support for critical latency devices, such as joysticksSupport for critical latency devices, such as joysticks – CSMA/CA channel access (data centric), slotted (beacon) or unslottedCSMA/CA channel access (data centric), slotted (beacon) or unslotted– Automatic network establishment by the PAN coordinatorAutomatic network establishment by the PAN coordinator – Dynamic device addressing,Dynamic device addressing, f flexible addressing formatlexible addressing format– Fully handshaked protocol for transfer reliabilityFully handshaked protocol for transfer reliability – Power management to ensure low power consumptionPower management to ensure low power consumption – 16 channels in the 2.4 GHz ISM band, 10 channels in the 915 MHz US 16 channels in the 2.4 GHz ISM band, 10 channels in the 915 MHz US

ISM band and one channel in the European 868 MHz bandISM band and one channel in the European 868 MHz band

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BluetoothBluetooth

A cable replacement technologyA cable replacement technology 1 Mb/s symbol rate1 Mb/s symbol rate Range 10+ metersRange 10+ meters Single chip radio + baseband Single chip radio + baseband

– at low power & low price point ($5)at low power & low price point ($5)

Why not use Wireless LANs?- power- cost

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BluetoothBluetooth

IdeaIdea– Universal radio interfaceUniversal radio interface for ad-hoc wireless for ad-hoc wireless

connectivityconnectivity– Interconnecting computer and peripherals, Interconnecting computer and peripherals,

handheld devices, PDAs, cell phones – handheld devices, PDAs, cell phones – replacement of IrDAreplacement of IrDA

– Embedded in other devicesEmbedded in other devices, goal: 5€/device , goal: 5€/device (2002: 50€/USB Bluetooth)(2002: 50€/USB Bluetooth)

– Short range (10 m),Short range (10 m), low power consumption, low power consumption, license-free 2.45 GHz ISMlicense-free 2.45 GHz ISM

– Voice and dataVoice and data transmission, approx. transmission, approx. 1 Mbit/s1 Mbit/s gross data rategross data rate

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BluetoothBluetooth

One of the first modules (Ericsson).

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Usage Scenarios ExamplesUsage Scenarios Examples

Data Access PointsData Access Points SynchronizationSynchronization HeadsetHeadset Conference TableConference Table Cordless ComputerCordless Computer Business Card ExchangeBusiness Card Exchange Instant PostcardInstant Postcard Computer SpeakerphoneComputer Speakerphone

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History and hi-History and hi-tech…tech…

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BluetoothBluetooth HistoryHistory

– 1994: Ericsson (Mattison/Haartsen), “MC-link” project1994: Ericsson (Mattison/Haartsen), “MC-link” project– Renaming of the project: Bluetooth according to Renaming of the project: Bluetooth according to Harald Harald

“Bl“Blåtand” åtand” Gormsen [son of Gorm], King of Denmark in the Gormsen [son of Gorm], King of Denmark in the 1010thth century century

– 1998: foundation of Bluetooth SIG, 1998: foundation of Bluetooth SIG, www.bluetooth.org– 1999: erection of a rune stone at Ericsson/Lund1999: erection of a rune stone at Ericsson/Lund– 2001: first consumer products for mass market, spec. version 2001: first consumer products for mass market, spec. version

1.1 released1.1 released

Special Interest GroupSpecial Interest Group– Original Original founding membersfounding members: Ericsson, Intel, IBM, Nokia, : Ericsson, Intel, IBM, Nokia,

ToshibaToshiba– Added promotersAdded promoters: 3Com, Agere (was: Lucent), Microsoft, : 3Com, Agere (was: Lucent), Microsoft,

MotorolaMotorola– > 2500 members> 2500 members– Common specification and certification of productsCommon specification and certification of products

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……and the real stoneand the real stoneLocated in Jelling, Denmark,erected by King Harald “Blåtand”in memory of his parents.The stone has three sides – one sideshowing a picture of Christ.

This could be the “original” colors of the stone. Inscription:“auk tani karthi kristna” (and made the Danes Christians)

Inscription:"Harald king executes these sepulchral monuments after Gorm, his father and Thyra, his mother. The Harald who won the whole of Denmark and Norway and turned the Danes to Christianity." Btw: Blåtand means “of dark complexion”

(not having a blue tooth…)

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CharacteristicsCharacteristics 2.4 GHz ISM band, 79 RF channels, 1 MHz carrier spacing2.4 GHz ISM band, 79 RF channels, 1 MHz carrier spacing

– Channel 0: 2402 MHz … channel 78: 2480 MHzChannel 0: 2402 MHz … channel 78: 2480 MHz– G-FSK modulation, 1-100 mW transmit powerG-FSK modulation, 1-100 mW transmit power

FHSS and TDDFHSS and TDD– Frequency hopping with 1600 hops/sFrequency hopping with 1600 hops/s– Hopping sequence in a pseudo random fashion, determined by a Hopping sequence in a pseudo random fashion, determined by a

mastermaster– Time division duplex for send/receive separationTime division duplex for send/receive separation

Voice link – SCO (Synchronous Connection Oriented)Voice link – SCO (Synchronous Connection Oriented)– FEC (forward error correction), no retransmission, 64 kbit/s duplex, FEC (forward error correction), no retransmission, 64 kbit/s duplex,

point-to-point, circuit switchedpoint-to-point, circuit switched Data link – ACL (Asynchronous ConnectionLess)Data link – ACL (Asynchronous ConnectionLess)

– Asynchronous, fast acknowledge, point-to-multipoint, up to 433.9 Asynchronous, fast acknowledge, point-to-multipoint, up to 433.9 kbit/s symmetric or 723.2/57.6 kbit/s asymmetric, packet switchedkbit/s symmetric or 723.2/57.6 kbit/s asymmetric, packet switched

TopologyTopology– Overlapping piconets (stars) forming a scatternetOverlapping piconets (stars) forming a scatternet

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Bluetooth Protocol StackBluetooth Protocol Stack

Radio

Baseband

Link Manager

Control

HostControllerInterface

Logical Link Control and Adaptation Protocol (L2CAP)Audio

TCS BIN SDP

OBEX

vCal/vCard

IP

NW apps.

TCP/UDP

BNEP

RFCOMM (serial line interface)

AT modemcommands

telephony apps.audio apps. mgmnt. apps.

AT: attention sequenceOBEX: object exchangeTCS BIN: telephony control protocol specification – binaryBNEP: Bluetooth network encapsulation protocol

SDP: service discovery protocolRFCOMM: radio frequency comm.

PPP

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Connection Connection ManagementManagement

Standby: do nothingInquiry: search for other devicesPage: connect to a specific deviceConnected: participate in a piconet

• In the beginning of the formation of a piconet, all devices are in SB mode, then one of the devices starts with an inquiry and becomes the “M” terminal.

• During the inquiry process, “M” registers all the SB terminals that then become “S” terminals. After the inquiry process, identification and timing of all “S” terminals is sent to “M” using FHS packets.

• The “M” terminal starts a connection with a PAGE message including its timing and ID to the “S” terminal.

• When the connection is established, the communication takes place, and at the end, the terminal can be sent back to SB, Hold, park or Sniff states.

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Connection Connection ManagementManagement

Park: release AMA, get PMA Sniff: listen periodically, not each slotHold: stop ACL, SCO still possible, possibly

participate in another piconet

• Hold, Park and Sniff are power-saving modes.

• The Hold mode is used when connecting several piconets or managing a low-power device.

• In the Hold mode, data transfer restarts as soon as the unit is out of this mode.

• In the Sniff mode, a slave listens to the piconet at reduced and programmable intervals according to the applications needs.

• In the Park mode a device gives up its MAC address but remains synchronized with the piconet.

• A Parked device does not participate in the traffic but occasionally listens to the traffic of “M” to resynchronize and check on broadcast messages.

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Interference Interference Between Bluetooth Between Bluetooth and 802.11and 802.11

The WLAN industry specified three levels of The WLAN industry specified three levels of overlapping: overlapping: – Interference:Interference: multiple wireless networks are said to multiple wireless networks are said to

interfere with one another if co-location causes interfere with one another if co-location causes significant performance degradationsignificant performance degradation

– Coexistence:Coexistence: multiple wireless networks are said to multiple wireless networks are said to coexist if they can be co-located without significant coexist if they can be co-located without significant impact on performance. It provides for the ability impact on performance. It provides for the ability of one system to perform a task in a shared of one system to perform a task in a shared frequency band with other systems that may or frequency band with other systems that may or may not be using the same rules for operationmay not be using the same rules for operation

– Inter-operation:Inter-operation: provides for an environment with provides for an environment with multiple wireless systems to perform a given task multiple wireless systems to perform a given task using a single set of rulesusing a single set of rules

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PiconetPiconet

Collection of devices connected in an ad hoc fashion

One unit acts as master and the others as slaves for the lifetime of the piconet

Master determines hopping pattern, slaves have to synchronize

Each piconet has a unique hopping pattern

Participation in a piconet = synchronization to hopping sequence

Each piconet has one master and up to 7 simultaneous slaves (> 200 could be parked)

M=MasterS=Slave

P=ParkedSB=Standby

M

S

P

SB

S

S

P

P

SB

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Forming a PiconetForming a Piconet All devices in a piconet hop togetherAll devices in a piconet hop together

– Master gives slaves Master gives slaves its clock and device IDits clock and device ID Hopping patternHopping pattern: determined by device ID (48 bit, unique worldwide): determined by device ID (48 bit, unique worldwide) Phase in hopping patternPhase in hopping pattern determined by clock determined by clock

AddressingAddressing– Active Member Address (AMA, 3 bit)Active Member Address (AMA, 3 bit)– Parked Member Address (PMA, 8 bit)Parked Member Address (PMA, 8 bit)

SBSB

SB

SB

SB

SB

SB

SB

SB

MS

P

SB

S

S

P

P

SB

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ScatternetScatternet Linking of multiple co-located piconets through the Linking of multiple co-located piconets through the

sharing of sharing of common master or slave devicescommon master or slave devices– Devices can be slave in one piconet and master of Devices can be slave in one piconet and master of

anotheranother Communication between piconetsCommunication between piconets

– Devices jumping back and forth between the Devices jumping back and forth between the piconetspiconets

M=MasterS=SlaveP=ParkedSB=Standby

M

S

P

SB

S

S

P

P

SB

M

S

S

P

SB

Piconets(each with a capacity of < 1 Mbit/s)