8-1©2008 Raj JainCSE574sWashington University in St. LouisWireless Personal Area Wireless Personal Area Networks: Part INetworks: Part IRaj JainProfessor of CSE Washington University in Saint LouisSaint Louis, MO [email protected]/Video recordings of this lecture are available on-line at:http://www.cse.wustl.edu/~jain/cse574-08/8-2©2008 Raj JainCSE574sWashington University in St. LouisOverviewOverview! Wireless Standards Overview! Bluetooth8-3©2008 Raj JainCSE574sWashington University in St. LouisWireless StandardsWireless Standards802.15.1Bluetooth802.15.3Personal Area Network (PAN)802.16/WiMAXFixed Wireless MANMetropolitan Area Network (MAN)802.11Wi-FiLocal Area Network (LAN)Wide Area Network (WAN)802.20Mobile2G, 2.5G, 3GCellular802.16eNomadic802.21Handoff802.15.4ZigBee802.22WRAN8-4©2008 Raj JainCSE574sWashington University in St. LouisDistance vs. Data RateDistance vs. Data RateData Rate (Mbps)RangeZigBee802.15.4802.15.3802.15.3a802.15.3cWPANWLANWMANWWANWiFi802.110.01 0.1 1 10 100 1000Bluetooth802.15.1IEEE 802.22WiMAXIEEE 802.16IEEE 802.20UWB8-5©2008 Raj JainCSE574sWashington University in St. LouisMobility vs. Data RateMobility vs. Data Rate802.15.3aUWB8-6©2008 Raj JainCSE574sWashington University in St. LouisBluetooth ProductsBluetooth Products! Printers, faxes, digital cameras…! 720 kbps to 10m! Competes with infrared, which has a range of 1m, requires line of sight and has a low data rateHeadsets Game Controller GPSAudio Keyboard8-7©2008 Raj JainCSE574sWashington University in St. LouisBluetoothBluetooth! Started with Ericsson's Bluetooth Project in 1994! Named after Danish king Herald Blatand (AD 940-981) who was fond of blueberries! Radio-frequency communication between cell phones over short distances! Intel, IBM, Nokia, Toshiba, and Ericsson formed Bluetooth SIG in May 1998! Version 1.0A of the specification came out in late 1999.! IEEE 802.15.1 approved in early 2002 is based on Bluetooth! Key Features:" Lower Power: 10 μA in standby, 50 mA while transmitting" Cheap: $5 per device" Small: 9 mm2single chips8-8©2008 Raj JainCSE574sWashington University in St. LouisBluetooth: DetailsBluetooth: Details! Frequency Range: 2402 - 2480 MHz (total 79 MHz band)23 MHz in some countries, e.g., Spain! Data Rate:1 Mbps (Nominal) 720 kbps (User) ! Channel Bandwidth:1 MHz! Range: Up to 10 m can be extended further! RF hopping: 1600 times/s ⇒ 625 μs/hop! Security: Challenge/Response Authentication. 128b Encryption! TX Output Power: " Class 1: 20 dBm Max. (0.1W) – 100m" Class 2: 4 dBm (2.5 mW) " Class 3: 0 dBm (1mW) – 10m! Ref: http://www.bluetooth.com/http://www.bluetooth.org/http://grouper.ieee.org/groups/802/15/index.html8-9©2008 Raj JainCSE574sWashington University in St. LouisPiconetPiconet! Piconet is formed by a master and many slaves" Up to 7 active slaves. Slaves can only transmit when requested by master" Up to 255 Parked slaves! Active slaves are polled by master for transmission! Each station gets a 8-bit parked address ⇒ 255 parked slaves/piconet! The parked station can join in 2ms.! Other stations can join in more time.! A device can participate in multiple piconets ⇒ complex schedule8-10©2008 Raj JainCSE574sWashington University in St. LouisFrequency Hopping SequencesFrequency Hopping Sequences! 625 μs slots! Time-division duplex (TDD) ⇒ Downstream and upstream alternate! Master starts in even numbered slots only.! Slaves start in odd numbered slots only! lsb of the clock indicates even or odd! Slaves can transmit in one slot right after receiving a packet from master! Packets = 1 slot, 3 slot, or 5 slots long! The frequency hop is skipped during a packet.Frequency 1Frequency 2Frequency 38-11©2008 Raj JainCSE574sWashington University in St. LouisBluetooth Packet FormatBluetooth Packet Format! Packets can be up to five slots long. 2745 bits. ! Access codes: " Channel access code identifies the piconet" Device access code for paging requests and response" Inquiry access code to discover units! Header: member address (3b), type code (4b), flow control, ack/nack (1b), sequence number, and header error check (8b)18b Header is encoded using 1/3 rate FEC resulting in 54b ! Synchronous traffic has periodic reserved slots.! Other slots can be allocated for asynchronous trafficData PayloadAccess CodeBaseband/Link Control Header72b 54b 0-2745b8-12©2008 Raj JainCSE574sWashington University in St. LouisBluetooth Operational StatesBluetooth Operational StatesStandbyInquiry PageTransmitConnectedPark HoldSniffDisconnectedConnectingActiveLow Power8-13©2008 Raj JainCSE574sWashington University in St. LouisBluetooth Operational States (Cont)Bluetooth Operational States (Cont)! Standby: Initial state! Inquiry: Master sends an inquiry packet. Slaves scan for inquiries and respond with their address and clock after a random delay (CSMA/CA)! Page: Master in page state invites devices to join the piconet. Page message is sent in 3 consecutive slots (3 frequencies). Slave enters page response state and sends page response including its device access code.! Master informs slave about its clock and address so that slave can participate in piconet. Slave computes the clock offset.! Connected: A short 3-bit logical address is assigned! Transmit:8-14©2008 Raj JainCSE574sWashington University in St. LouisEnergy Management in BluetoothEnergy Management in BluetoothThree inactive states:1. Hold: No Asynchronous Connection List (ACL). Synchronous Connection Oriented (SCO) continues. Node can do something else: scan, page, inquire2. Sniff: Low-power mode. Slave listens after fixed sniff intervals.3. Park: Very Low-power mode. Gives up its 3-bit active member address and gets an 8-bit parked member address.! Packets for parked stations are broadcast to 3-bit zero address.SniffPark8-15©2008 Raj JainCSE574sWashington University in St. LouisPower per MBPower per MB0.03200uW55Mb802.15.38.01mW1Mb802.15.129.6200mW54Mb802.11a7.450mW54Mb802.11g36.450mW11Mb802.11bmJoules/MBTX PowerBit rateType8-16©2008 Raj JainCSE574sWashington University in St. LouisBluetooth Protocol StackBluetooth Protocol Stack! RF = Frequency hopping GFSK modulation! Baseband: Frequency hop selection, connection, MACApplications (Profiles)TCS RFCOMM SDP ControlAudioL2CAPLink ManagerBasebandRFTransportMiddlewareApplication8-17©2008 Raj JainCSE574sWashington University in St. LouisBaseband LayerBaseband Layer! Each device has a 48-bit IEEE MAC address! 3 parts: " Lower address part (LAP) – 24
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