Wireless LANs. Characteristics of wireless LANs. Comparison: infrared vs. radio transmission. Design goals for wireless LANs

Transcription

1 Characerisics of wireless LANs Characerisics IEEE HY AC Roaming.11a, b, g, h, i Wireless LANs Blueooh Comparison Advanages very flexible wihin he recepion area Ad-hoc neworks wihou previous planning possible (almos) no wiring difficulies (e.g. hisoric buildings, firewalls) more robus agains disasers like, e.g., earhquakes, fire - or users pulling a plug... Disadvanages ypically very low bandwidh compared o wired neworks (1-10 bi/s) many proprieary soluions, especially for higher bi-raes, sandards ake heir ime (e.g. IEEE ) producs have o follow many naional resricions if working wireless, i akes a vary long ime o esablish global soluions like, e.g., IT-2000 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 1 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 2 Design goals for wireless LANs Comparison: infrared vs. radio ransmission global, seamless operaion low power for baery use no special permissions or licenses needed o use he LAN robus ransmission echnology simplified sponaneous cooperaion a meeings easy o use for everyone, simple managemen proecion of invesmen in wired neworks securiy (no one should be able o read my daa), privacy (no one should be able o collec user profiles), safey (low radiaion) ransparency concerning applicaions and higher layer proocols, bu also locaion awareness if necessary Infrared uses IR diodes, diffuse ligh, muliple reflecions (walls, furniure ec.) Advanages simple, cheap, available in many mobile devices no licenses needed simple shielding possible Disadvanages inerference by sunligh, hea sources ec. many hings shield or absorb IR ligh low bandwidh Example IrDA (Infrared Daa Associaion) inerface available everywhere Radio ypically using he license free I band a 2.4 GHz Advanages experience from wireless WAN and mobile phones can be used coverage of larger areas possible (radio can penerae walls, furniure ec.) Disadvanages very limied license free frequency bands shielding more difficul, inerference wih oher elecrical devices Example WaveLAN, HIERLAN, Blueooh Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 3 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 4

2 Comparison: infrasrucure vs. ad-hoc neworks Archiecure of an infrasrucure nework infrasrucure nework A ad-hoc nework A wired nework A: Access oin A TA 1 E LAN B 1 Access oin B 2 oral Disribuion ysem Access oin 802.x LAN TA LAN TA 3 aion (TA) erminal wih access mechanisms o he wireless medium and radio conac o he access poin Basic ervice e (B) group of saions using he same radio frequency Access oin saion inegraed ino he wireless LAN and he disribuion sysem oral bridge o oher (wired) neworks Disribuion ysem inerconnecion nework o form one logical nework (EE: Exended ervice e) based on several B Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 5 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing Archiecure of an ad-hoc nework IEEE sandard TA LAN IB 1 TA 2 TA 3 Direc communicaion wihin a limied range aion (TA): erminal wih access mechanisms o he wireless medium Independen Basic ervice e (IB): group of saions using he same radio frequency mobile erminal applicaion access poin infrasrucure nework applicaion fixed erminal TC TC IB 2 I LLC LLC I LLC TA AC AC AC AC TA LAN HY HY HY HY Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 7 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 8

3 Layers and funcions hysical layer AC access mechanisms, fragmenaion, encrypion AC anagemen synchronizaion, roaming, IB, power managemen HY DLC LLC AC LC D AC anagemen HY anagemen LC hysical Layer Convergence roocol clear channel assessmen signal (carrier sense) D hysical edium Dependen modulaion, coding HY anagemen channel selecion, IB aion anagemen coordinaion of all managemen funcions aion anagemen 3 versions: 2 radio (yp. 2.4 GHz), 1 IR daa raes 1 or 2 bi/s FH (Frequency Hopping pread pecrum) spreading, despreading, signal srengh, yp. 1 bi/s min. 2.5 frequency hops/s (UA), wo-level GFK modulaion D (Direc equence pread pecrum) DBK modulaion for 1 bi/s (Differenial Binary hase hif Keying), DQK for 2 bi/s (Differenial Quadraure K) preamble and header of a frame is always ransmied wih 1 bi/s, res of ransmission 1 or 2 bi/s chipping sequence: +1, -1, +1, +1, -1, +1, +1, +1, -1, -1, -1 (Barker code) max. radiaed power 1 W (UA), 100 mw (EU), min. 1mW Infrared nm, diffuse ligh, yp. 10 m range Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 9 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 10 FH HY packe forma ynchronizaion synch wih paern FD (ar Frame Delimier) sar paern LW (LC_DU Lengh Word) lengh of payload incl. 32 bi CRC of payload, LW < 4096 F (LC ignaling Field) daa of payload (1 or 2 bi/s) HEC (Header Error Check) CRC wih x 16 +x 12 +x variable bis synchronizaion FD LW F HEC payload ynchronizaion D HY packe forma synch., gain seing, energy deecion, frequency offse compensaion FD (ar Frame Delimier) ignal ervice daa rae of he payload (0A: 1 bi/s DBK; 14: 2 bi/s DQK) fuure use, 00: complian HEC (Header Error Check) Lengh proecion of signal, service and lengh, x 16 +x 12 +x 5 +1 lengh of he payload variable bis synchronizaion FD signal service lengh HEC payload LC preamble LC header LC preamble LC header Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 11 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 12

4 AC layer I - DFWAC AC layer II Traffic services Asynchronous Daa ervice (mandaory) exchange of daa packes based on bes-effor suppor of broadcas and mulicas Time-Bounded ervice (opional) implemened using CF (oin Coordinaion Funcion) Access mehods (Disribued Foundaion Wireless AC: DFWAC) DFWAC-DCF CA/CA (mandaory) collision avoidance via randomized back-off mechanism packe for acknowledgemens (no for broadcass) DFWAC-DCF w/ RT/CT (opional) avoids hidden erminal problem DFWAC- CF (opional) access poin polls erminals according o a lis rioriies defined hrough differen iner frame spaces no guaraneed, hard prioriies (hor Iner Frame pacing) highes prioriy, for, CT, polling response IF (CF IF) medium prioriy, for ime-bounded service using CF (DCF, Disribued Coordinaion Funcion IF) lowes prioriy, for asynchronous daa service medium busy IF conenion nex frame direc access if medium is free Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 13 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing CA/CA access mehod I compeing saions - simple version conenion window (randomized back-off mechanism) saion 1 bo e bo r bo e bo r bo e busy medium busy nex frame bo e busy direc access if medium is free slo ime saion 2 busy saion 3 saion ready o send sars sensing he medium (Carrier ense based on CCA, Clear Channel Assessmen) saion 4 bo e busy bo e bo r if he medium is free for he duraion of an Iner-Frame pace (IF), he saion can sar sending (IF depends on service ype) if he medium is busy, he saion has o wai for a free IF, hen he saion mus addiionally wai a random back-off ime (collision avoidance, muliple of slo-ime) if anoher saion occupies he medium during he back-off ime of he saion, he back-off imer sops (fairness) saion 5 busy bo e bo r bo e busy bo e bo r medium no idle (frame, ack ec.) bo e elapsed backoff ime packe arrival a AC bo r residual backoff ime Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 15 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 16

5 CA/CA access mehod II DFWAC ending unicas packes saion has o wai for before sending daa receivers acknowledge a once (afer waiing for ) if he packe was received correcly (CRC) auomaic reransmission of daa packes in case of ransmission errors ending unicas packes saion can send RT wih reservaion parameer afer waiing for (reservaion deermines amoun of ime he daa packe needs he medium) acknowledgemen via CT afer by receiver (if ready o receive) sender can now send daa a once, acknowledgemen via oher saions sore medium reservaions disribued via RT and CT sender receiver daa sender receiver RT CT daa oher saions waiing ime conenion daa oher saions NAV (RT) NAV (CT) defer access conenion daa Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 17 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 18 Fragmenaion DFWAC-CF I sender receiver RT CT frag 1 1 frag 2 2 medium busy poin coordinaor 0 1 IF D 1 uperframe D 2 oher saions NAV (RT) NAV (CT) NAV (frag 1 ) NAV ( 1 ) conenion daa wireless saions saions NAV U 1 NAV U 2 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 19 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 20

6 DFWAC-CF II poin coordinaor wireless saions saions NAV D 3 IF D 4 U 4 NAV conenion free period CFend conenion period Types Frame forma conrol frames, managemen frames, daa frames equence numbers imporan agains duplicaed frames due o los s Addresses receiver, ransmier (physical), B idenifier, sender (logical) iscellaneous byes duraion (for NAV) / id, checksum, frame conrol, daa WE: wired equivalen privacy power managemen se o 1 => power-save mode afer successful frame ransmission order: received frames mus be processed in sric order Duraion/ ID Address 1 Address 2 Address 3 equence Conrol Frame Conrol roocol version 1 To Type ubype D ore Frag ower Rery gm Address Daa 4 bis From D ore Daa WE Order CRC Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 21 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 22 AC address forma pecial Frames:, RT, CT scenario o D from address 1 address 2 address 3 address 4 D ad-hoc nework 0 0 DA A BID - infrasrucure 0 1 DA BID A - nework, from A infrasrucure 1 0 BID A DA - nework, o A infrasrucure nework, wihin D 1 1 RA TA DA A Acknowledgemen Reques To end RT byes Frame Duraion Receiver CRC Conrol Address byes Frame Duraion Receiver Transmier CRC Conrol Address Address D: Disribuion ysem A: Access oin DA: Desinaion Address A: ource Address BID: Basic ervice e Idenifier RA: Receiver Address TA: Transmier Address Clear To end CT byes Frame Duraion Receiver CRC Conrol Address Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 23 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 24

7 AC managemen ynchronizaion using a Beacon (infrasrucure) ynchronizaion ry o find a LAN, ry o say wihin a LAN synchronizaion of inernal clocks generaion of beacon signals ower managemen beacon inerval sleep-mode wihou missing a message periodic sleep, frame buffering Associaion/Reassociaion inegraion ino a LAN roaming, i.e. change neworks by changing access poins scanning, i.e. acive search for a nework access poin medium B B B B busy busy busy busy value of he imesamp B beacon frame IB - anagemen Informaion Base sore all parameers represening he curren sae of a wireless saion and an access poin Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 25 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 26 ynchronizaion using a Beacon (ad-hoc) ower managemen saion 1 beacon inerval B 1 B 1 saion 2 B 2 B 2 medium busy busy busy busy value of he imesamp B beacon frame random delay Idea: swich he ransceiver off if no needed aes of a saion: sleep and awake Timing ynchronizaion Funcion (TF) saions wake up a he same ime Infrasrucure Traffic Indicaion ap (TI) lis of unicas receivers ransmied by A Delivery Traffic Indicaion ap (DTI) Ad-hoc lis of broadcas/mulicas receivers ransmied by A Ad-hoc Traffic Indicaion ap (ATI) announcemen of receivers by saions buffering frames more complicaed - no cenral A collision of ATIs possible (scalabiliy?) Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 27 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 28

8 ower saving wih wake-up paerns (infrasrucure) ower saving wih wake-up paerns (ad-hoc) TI inerval DTI inerval ATI window beacon inerval access poin medium D B busy T T d D busy busy busy B B saion 1 A D B 1 1 B saion 2 B 2 a d 2 saion T TI D DTI p awake d B beacon frame random delay A ransmi ATI D ransmi daa B broadcas/mulicas p poll d daa ransmission o/from he saion awake a acknowledge ATI d acknowledge daa Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 29 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing Roaming (moving beween access poins) WLAN: IEEE b No or bad connecion? Then perform: canning scan he environmen passive scanning: lisen ino he medium for beacon signals acive scanning: send probes ino he medium and wai for an answer Reassociaion Reques saion sends a reques o one or several A(s) Reassociaion Response success: A has answered, saion can now paricipae failure: coninue scanning A acceps Reassociaion Reques signal he new saion o he disribuion sysem he disribuion sysem updaes is daa base (i.e., locaion informaion) ypically, he disribuion sysem now informs he old A so i can release resources Daa rae 1, 2, 5.5, 11 bi/s, depending on NR User daa rae max. approx. 6 bi/s Transmission range 300m oudoor, 30m indoor ax. daa rae ~10m indoor Frequency Free 2.4 GHz I-band ecuriy Limied, WE insecure, ID Cos 100 adaper, 250 base saion, dropping Availabiliy any producs, many vendors Connecion se-up ime Connecionless/always on Qualiy of ervice Typ. Bes effor, no guaranees (unless polling is used, limied suppor in producs) anageabiliy Limied (no auomaed key disribuion, sym. Encrypion) pecial Advanages/Disadvanages Advanage: many insalled sysems, lo of experience, available worldwide, free I-band, many vendors, inegraed in lapops, simple sysem Disadvanage: heavy inerference on I-band, no service guaranees, slow relaive speed only Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 31 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 32

9 IEEE b HY frame formas Channel selecion (non-overlapping) Long LC DU forma variable bis synchronizaion FD signal service lengh HEC payload Europe (ETI) channel 1 channel 7 channel 13 LC preamble LC header 192 µs a 1 bi/s DBK 1, 2, 5.5 or 11 bi/s hor LC DU forma (opional) variable bis shor synch. FD signal service lengh HEC payload Hz [Hz] U (FCC)/Canada (IC) channel 1 channel 6 channel 11 LC preamble (1 bi/s, DBK) LC header (2 bi/s, DQK) 96 µs 2, 5.5 or 11 bi/s Hz [Hz] Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 33 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 34 WLAN: IEEE a IEEE a HY frame forma Daa rae 6, 9, 12, 18, 24, 36, 48, 54 bi/s, depending on NR User hroughpu (1500 bye packes): 5.3 (6), 18 (24), 24 (36), 32 (54) 6, 12, 24 bi/s mandaory Transmission range 100m oudoor, 10m indoor E.g., 54 bi/s up o 5 m, 48 up o 12 m, 36 up o 25 m, 24 up o 30m, 18 up o 40 m, 12 up o 60 m Frequency Free , , GHz I-band ecuriy Limied, WE insecure, ID Cos 280 adaper, 500 base saion Availabiliy ome producs, some vendors Connecion se-up ime Connecionless/always on Qualiy of ervice Typ. bes effor, no guaranees (same as all producs) anageabiliy Limied (no auomaed key disribuion, sym. Encrypion) pecial Advanages/Disadvanages Advanage: fis ino 802.x sandards, free I-band, available, simple sysem, uses less crowded 5 GHz band Disadvanage: sronger shading due o higher frequency, no Qo variable 6 variable rae reserved lengh pariy ail service payload ail pad LC header LC preamble signal daa 12 1 variable 6 bi/s 6, 9, 12, 18, 24, 36, 48, 54 bi/s bis symbols Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 35 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 36

10 Operaing channels for a / U U-NII OFD in IEEE a (and HiperLAN2) channel [Hz] 16.6 Hz OFD wih 52 used subcarriers (64 in oal) 48 daa + 4 pilo (plus 12 virual subcarriers) khz spacing pilo khz channel cener frequency = *channel number [Hz] [Hz] 16.6 Hz channel cener frequency subcarrier number Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 37 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 38 WLAN: IEEE fuure developmens (08/2002) Blueooh d: Regulaory Domain Updae compleed e: AC Enhancemens Qo ongoing Enhance he curren AC o expand suppor for applicaions wih Qualiy of ervice requiremens, and in he capabiliies and efficiency of he proocol f: Iner-Access oin roocol ongoing Esablish an Iner-Access oin roocol for daa exchange via he disribuion sysem g: Daa Raes > 20 bi/s a 2.4 GHz; 54 bi/s, OFD ongoing h: pecrum anaged a (DC, TC) ongoing i: Enhanced ecuriy echanisms ongoing Enhance he curren AC o provide improvemens in securiy. udy Groups 5 GHz (harmonizaion ETI/IEEE) closed Radio Resource easuremens sared High Throughpu sared Idea Universal radio inerface for ad-hoc wireless conneciviy Inerconnecing compuer and peripherals, handheld devices, DAs, cell phones replacemen of IrDA Embedded in oher devices, goal: 5 /device (2002: 50 /U blueooh) hor range (10 m), low power consumpion, license-free 2.45 GHz I Voice and daa ransmission, approx. 1 bi/s gross daa rae One of he firs modules (Ericsson). Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 39 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 40

11 Blueooh Hisory and hi-ech Hisory 1994: Ericsson (aison/haarsen), uli-communicaor (C)-link projec Renaming of he projec: Blueooh according o Harald Blåand Gormsen [son of Gorm], King of Denmark in he 10 h cenury 1998: foundaion of Blueooh IG, (was: ) 1999: erecion of a rune sone a Ercisson/Lund ;-) 2001: firs consumer producs for mass marke, spec. version 1.1 released pecial Ineres Group Original founding members: Ericsson, Inel, IB, Nokia, Toshiba Added promoers: 3Com, Agere (was: Lucen), icrosof, oorola > 2500 members Common specificaion and cerificaion of producs 1999: Ericsson mobile communicaions AB rese denna sen ill minne av Harald Blåand, som fick ge si namn å en ny eknologi för rådlös, mobil kommunikaion. Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 41 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 42 and he real rune sone Characerisics Inscripion: "Harald king execues hese sepulchral monumens afer Gorm, his faher and Thyra, his moher. The Harald who won he whole of Denmark and Norway and urned he Danes o Chrisianiy." Bw: Blåand means of dark complexion (no having a blue ooh ) Locaed in Jelling, Denmark, ereced by King Harald Blåand in memory of his parens. The sone has hree sides one side showing a picure of Chris. This could be he original colors of he sone. Inscripion: auk ani karhi krisna (and made he Danes Chrisians) 2.4 GHz I band, 79 (23) RF channels, 1 Hz carrier spacing Channel 0: 2402 Hz channel 78: 2480 Hz G-FK modulaion, mw ransmi power FH and TDD Frequency hopping wih 1600 hops/s Hopping sequence in a pseudo random fashion, deermined by a maser Time division duplex for send/receive separaion Voice link CO (ynchronous Connecion Oriened) FEC (forward error correcion), no reransmission, 64 kbi/s duplex, poino-poin, circui swiched Daa link ACL (Asynchronous ConnecionLess) Asynchronous, fas acknowledge, poin-o-mulipoin, up o kbi/s symmeric or 723.2/57.6 kbi/s asymmeric, packe swiched Topology Overlapping picones (sars) forming a scaerne Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 43 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 44

12 icone Collecion of devices conneced in an ad hoc fashion One uni acs as maser and he ohers as slaves for he lifeime of he picone aser deermines hopping paern, slaves have o synchronize Each picone has a unique hopping paern aricipaion in a picone = synchronizaion o hopping sequence Each picone has one maser and up o 7 simulaneous slaves (> 200 could be parked) =aser =lave =arked =andby Forming a picone All devices in a picone hop ogeher aser gives slaves is clock and device ID Addressing Hopping paern: deermined by device ID (48 bi, unique worldwide) hase in hopping paern deermined by clock Acive ember Address (AA, 3 bi) arked ember Address (A, 8 bi) Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 45 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 46 caerne Linking of muliple co-locaed picones hrough he sharing of common maser or slave devices Devices can be slave in one picone and maser of anoher Communicaion beween picones Devices jumping back and forh beween he picones =aser =lave =arked =andby Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 47 icones (each wih a capaciy of < 1 bi/s) audio apps. Audio Blueooh proocol sack NW apps. TC/UD I BNE vcal/vcard OBEX Logical Link Conrol and Adapaion roocol (L2CA) Baseband Radio AT modem commands RFCO (serial line inerface) AT: aenion sequence OBEX: objec exchange TC BIN: elephony conrol proocol specificaion binary BNE: Blueooh nework encapsulaion proocol elephony apps. TC BIN mgmn. apps. D Link anager Conrol D: service discovery proocol RFCO: radio frequency comm. Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 48 Hos Conroller Inerface

13 Frequency selecion during daa ransmission Baseband 625 µs f k f k+1 f k+2 f k+3 f k+4 f k f k+3 f k+4 f k+5 f k+6 f k+5 f k+6 icone/channel definiion Low-level packe definiion Access code Channel, device access, e.g., derived from maser acke header 1/3-FEC, acive member address (broadcas + 7 slaves), link ype, alernaing bi ARQ/EQ, checksum 68(72) bis access code packe header payload f k f k+1 f k (4) bis preamble sync. (railer) A address ype flow ARQN EQN HEC Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 49 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 50 CO payload ypes ACL ayload ypes payload (30) payload (0-343) HV1 audio (10) FEC (20) header (1/2) payload (0-339) CRC (2) HV2 audio (20) FEC (10) D1 header (1) payload (0-17) 2/3 FEC CRC (2) HV3 audio (30) DH1 header (1) payload (0-27) CRC (2) (byes) DV audio (10) header (1) payload (0-9) 2/3 FEC CRC (2) D3 header (2) payload (0-121) 2/3 FEC CRC (2) (byes) DH3 header (2) payload (0-183) CRC (2) D5 DH5 header (2) payload (0-224) 2/3 FEC header (2) payload (0-339) CRC (2) CRC (2) AUX1 header (1) payload (0-29) Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 51 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 52

14 ACL 1 slo 3 slo 5 slo CO Baseband daa raes ayload User ymmeric Asymmeric Header ayload max. Rae max. Rae [kbi/s] Type [bye] [bye] FEC CRC [kbi/s] Forward Reverse D /3 yes DH no yes D /3 yes DH no yes D /3 yes DH no yes AUX no no HV1 na 10 1/3 no 64.0 HV2 na 20 2/3 no 64.0 HV3 na 30 no no 64.0 DV 1 D 10+(0-9) D 2/3 D yes D D Daa edium/high rae, High-qualiy Voice, Daa and Voice Baseband link ypes olling-based TDD packe ransmission 625µs slos, maser polls slaves CO (ynchronous Connecion Oriened) Voice eriodic slo assignmen (wo consecuive slos: forward and reurn) 64 kbi/s full-duplex, poin-o-poin, no reransmission ACL (Asynchronous ConnecionLess) Daa Variable packe size (1,3,5 slos), asymmeric bandwidh, poin-o-mulipoin Fas auomaic repea reques (ARQ) scheme for reliable ransmission aser uses a polling scheme laves may only answer if i has been addressed in he preceding slo CO ACL CO ACL CO ACL CO ACL ATER f 0 f 4 f 6 f 8 f 12 f 14 f 18 f 20 LAVE 1 LAVE 2 f 1 f 7 f 9 f 13 f 19 f 5 f 21 f 17 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 53 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 54 Robusness Baseband saes of a Blueooh device low frequency hopping wih hopping paerns deermined by a maser roecion from inerference on cerain frequencies eparaion from oher picones (FH-CDA) Reransmission ACL only Forward Error Correcion CO and ACL ATER Error in payload (no header!) A C C F H NAK deach sandby ransmi AA inquiry page conneced AA unconneced connecing acive park A hold AA sniff AA low power LAVE 1 LAVE 2 B D E G G andby: do nohing Inquire: search for oher devices (send an inquiry access code: IAC) age: connec o a specific device (device address and iming info. reqd. by maser Conneced: paricipae in a picone ark: release AA, ge A niff: lisen periodically, no each slo (maser designaes a reduced no. of slos for ransmissions o slaves) Hold: sop ACL, CO sill possible, possibly paricipae in anoher picone Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 55 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 56

15 Example: ower consumpion/cr BlueCore2 Example: Blueooh/U adaper (2002: 50 ) Typical Average Curren Consumpion (1) VDD=1.8V Temperaure = 20 C ode CO connecion HV3 (1s inerval niff ode) (lave) 26.0 ma CO connecion HV3 (1s inerval niff ode) (aser) 26.0 ma CO connecion HV1 (lave) 53.0 ma CO connecion HV1 (aser) 53.0 ma ACL daa ransfer 115.2kbps UART (aser) 15.5 ma ACL daa ransfer 720kbps U (lave) 53.0 ma ACL daa ransfer 720kbps U (aser) 53.0 ma ACL connecion, niff ode 40ms inerval, 38.4kbps UART 4.0 ma ACL connecion, niff ode 1.28s inerval, 38.4kbps UART 0.5 ma arked lave, 1.28s beacon inerval, 38.4kbps UART 0.6 ma andby ode (Conneced o hos, no RF aciviy) 47.0 µa Deep leep ode(2) 20.0 µa Noes: (1) Curren consumpion is he sum of boh BC212015A and he flash. (2) Curren consumpion is for he BC212015A device only. (ore: ) Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 57 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 58 L2CA - Logical Link Conrol and Adapaion roocol L2CA logical channels L2CA: available for ACLs only imple daa link proocol on op of baseband Connecion oriened, connecionless, and signalling channels connecion-oriened channels bi-direcional suppor Qo flow specificaions for each direcion connecionless channels Unidirecional ypically used for broadcass from a maser o is slave(s) signalling channels exchange signalling exchanges beween L2CA eniies roocol muliplexing RFCO, D, elephony conrol lave aser lave L2CA L2CA L2CA 2 d 1 1 d d d d 1 1 d d 2 baseband baseband baseband egmenaion & reassembly up o 64kbye user daa, 16 bi CRC used from baseband Qo flow specificaion per channel follows RFC 1363, specifies delay, jier, burss, bandwidh signalling ACL connecionless connecion-oriened Group absracion creae/close group, add/remove member add slaves o, and remove slaves from a mulicas group Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 59 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 60

16 L2CA packe formas ecuriy Connecionless DU byes lengh CID=2 payload IN (1-16 bye) E 2 User inpu (iniializaion) airing Auhenicaion key generaion (possibly permanen sorage) IN (1-16 bye) E 2 Connecion-oriened DU byes lengh CID payload link key (128 bi) E 3 Auhenicaion Encrypion key generaion (emporary sorage) link key (128 bi) E 3 ignalling command DU 2 2 byes lengh CID=1 One or more commands encrypion key (128 bi) Keysream generaor Encrypion encrypion key (128 bi) Keysream generaor code ID lengh daa Daa payload key Ciphering Cipher daa payload key Daa Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 61 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 62 ecuriy: rocedure D ervice Discovery roocol E2 E3 inpus: IN, device address, and random numbers inpus: link key, random number generaed by a verifier, and device address of he claiman Keysream generaor inpus: encrypion key, device address, and curren clock eri beer securiy han in IEEE Weaknesses INs ofen fixed some keys permanenly sored on he devices qualiy of random number generaors no specified Inquiry/response proocol for discovering services earching for and browsing services in radio proximiy Adaped o he highly dynamic environmen Can be complemened by ohers like L, Jini, aluaion, Defines discovery only, no he usage of services Caching of discovered services Gradual discovery ervice record forma Informaion abou services provided by aribues Aribues are composed of an 16 bi ID (name) and a value values may be derived from 128 bi Universally Unique Idenifiers (UUID) Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 63 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 64

17 RFCO Addiional proocols o suppor legacy proocols/apps. Emulaion of a serial por (suppors a large base of legacy applicaions) Allows muliple pors over a single physical channel Telephony Conrol roocol pecificaion (TC) Call conrol (seup, release) OBEX WA Group managemen Exchange of objecs, IrDA replacemen Ineracing wih applicaions on cellular phones rofiles Represen defaul soluions for a cerain usage model Verical slice hrough he proocol sack Applicaions Basis for ineroperabiliy Generic Access rofile ervice Discovery Applicaion rofile Cordless Telephony rofile Inercom rofile erial or rofile Headse rofile Dial-up Neworking rofile Addiional rofiles Advanced Audio Disribuion rofiles Fax rofile AN Audio Video Remoe Conrol LAN Access rofile Basic rining Generic Objec Exchange rofile Basic Imaging Objec ush rofile Exended ervice Discovery File Transfer rofile Generic Audio Video Disribuion ynchronizaion rofile Hands Free Hardcopy Cable Replacemen roocols Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 65 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 66 WAN: IEEE Blueooh WAN: IEEE fuure developmens 1 Daa rae ynchronous, connecion-oriened: 64 kbi/s Asynchronous, connecionless kbi/s symmeric / 57.6 kbi/s asymmeric Transmission range O (ersonal Operaing pace) up o 10 m wih special ransceivers up o 100 m Frequency Free 2.4 GHz I-band ecuriy Challenge/response (AFER+), hopping sequence Cos 50 adaper, drop o 5 if inegraed Availabiliy Inegraed ino some producs, several vendors Connecion se-up ime Depends on power-mode ax. 2.56s, avg. 0.64s Qualiy of ervice Guaranees, ARQ/FEC anageabiliy ublic/privae keys needed, key managemen no specified, simple sysem inegraion pecial Advanages/Disadvanages Advanage: already inegraed ino several producs, available worldwide, free I-band, several vendors, simple sysem, simple ad-hoc neworking, peer o peer, scaernes Disadvanage: inerference on I-band, limied range, max. 8 devices/nework&maser, high se-up laency : Coexisance Coexisence of Wireless ersonal Area Neworks (802.15) and Wireless Local Area Neworks (802.11), quanify he muual inerference : High-Rae andard for high-rae (20bi/s or greaer) WANs, while sill lowpower/low-cos Daa Raes: 11, 22, 33, 44, 55 bi/s Qualiy of ervice isochronous proocol Ad hoc peer-o-peer neworking ecuriy Low power consumpion Low cos Designed o mee he demanding requiremens of porable consumer imaging and mulimedia applicaions Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 67 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 68

18 WAN: IEEE fuure developmens : Low-Rae, Very Low-ower Low daa rae soluion wih muli-monh o muli-year baery life and very low complexiy oenial applicaions are sensors, ineracive oys, smar badges, remoe conrols, and home auomaion Daa raes of kbi/s, laency down o 15 ms aser-lave or eer-o-eer operaion uppor for criical laency devices, such as joysicks CA/CA channel access (daa cenric), sloed (beacon) or unsloed Auomaic nework esablishmen by he AN coordinaor Dynamic device addressing, flexible addressing forma Fully handshaked proocol for ransfer reliabiliy ower managemen o ensure low power consumpion 16 channels in he 2.4 GHz I band, 10 channels in he 915 Hz U I band and one channel in he European 868 Hz band I band inerference any sources of inerference icrowave ovens, microwave lighning , b, g, , Home RF Even analog TV ransmission, surveillance Unlicensed meropolian area neworks Levels of inerference hysical layer: inerference acs like noise pread specrum ries o minimize his FEC/inerleaving ries o correc AC layer: algorihms no harmonized E.g., Blueooh migh confuse OLD NEW Fusion Lighing, Inc. Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 69 Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing vs.(?) /Blueooh Blueooh may ac like a rogue member of he nework f [Hz] Does no know anyhing abou gaps, iner frame spacing ec b bye 100 bye 100 bye 1000 bye 500 bye IEEE discusses hese problems roposal: Adapive Frequency Hopping 100 bye a non-collaboraive Coexisence echanism Real effecs? any differen opinions, publicaions, ess, formulae, Resuls from complee breakdown o almos no effec Blueooh (FH) seems more robus han b (D) 100 bye 500 bye 100 bye 3 channels (separaed by insallaion) channels (separaed by hopping paern) Dr. Ka-Cheong Leung CI 7304 The Wireless Inerne and obile Compuing 71