4/20/09. Wireless LANs. Mobile Communication Technology according to IEEE (examples) Characteristics of wireless LANs. WiFi. ZigBee

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1 Wireless LANs Characerisics IEEE (PHY, MAC, Roaming,.11a, b, g, h, i, n z) Blueooh / IEEE x IEEE /.20/.21/.22 RFID Comparison Mobile Communicaion Technology according o IEEE (examples) Local wireless neworks WLAN Personal wireless nes WPAN WiFi a b ZigBee h i/e/ /n/ /z g a/b/c/d/e ,.6 (WBAN) b/c Blueooh Wireless disribuion neworks WMAN (Broadband Wireless Access) WiMAX + Mobiliy [ (Mobile Broadband Wireless Access)] e (addiion o.16 for mobile devices) Characerisics of wireless LANs Advanages very flexible wihin he recepion area ad-hoc neworks wihou previous planning possible (almos) no wiring difficulies (e.g., hisoric buildings) more robus agains disasers like, e.g., earhquakes, fire - or users pulling a plug... cheap (addiional users don increase cos) Disadvanages ypically very low bandwidh compared o wired neworks (1-10 Mbi/s) due o shared medium, more inerferences many proprieary soluions, especially for higher bi-raes, sandards ake heir ime (e.g., IEEE n) producs have o follow many naional regulaions, akes ime for global soluions (IMT-2000). safey/securiy 1

2 Design goals for wireless LANs 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 Comparison: infrared vs. radio ransmission 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 IM 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.) higher ransmission raes Disadvanages very limied license free frequency bands shielding more difficul, inerference wih oher elecrical devices Example many differen producs Comparison: infrasrucure vs. ad-hoc neworks infrasrucure nework AP AP wired nework AP: Access Poin AP ad-hoc nework 2

3 Archiecure of an infrasrucure nework TA 1 E LAN 802.x LAN B 1 Poral Access Poin Disribuion ysem Access Poin B 2 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 Poin saion inegraed ino he wireless LAN and he disribuion sysem Poral bridge o oher (wired) neworks Disribuion ysem inerconnecion nework o form one logical nework (EE: Exended ervice e) based on several B TA LAN TA Archiecure of an ad-hoc nework 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 IB 2 TA 5 TA LAN IEEE sandard mobile erminal fixed erminal applicaion TCP IP LLC MAC PHY access poin LLC MAC MAC PHY PHY infrasrucure nework applicaion TCP IP LLC MAC PHY 3

4 Physical layer 3 versions: 2 radio (yp. 2.4 GHz), 1 IR daa raes 1 or 2 Mbi/s FH (Frequency Hopping pread pecrum) spreading, despreading, signal srengh, yp. 1 Mbi/s min. 2.5 frequency hops/s (UA), GFK modulaion D (Direc equence pread pecrum) DBPK modulaion for 1 Mbi/s (Differenial Binary Phase hif Keying), DQPK for 2 Mbi/s (Differenial Quadraure PK) preamble and header of a frame is always ransmied wih 1 Mbi/s, res of ransmission 1 or 2 Mbi/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 carrier deecion, energy deecion, synchronizaion FH PHY packe forma ynchronizaion synch wih paern FD (ar Frame Delimier) sar paern PLW (PLCP_PDU Lengh Word) lengh of payload incl. 32 bi CRC of payload, PLW < 4096 PF (PLCP ignaling Field) daa of payload (1 or 2 Mbi/s) HEC (Header Error Check) CRC wih x 16 +x 12 +x variable bis synchronizaion FD PLW PF HEC payload PLCP preamble PLCP header D PHY packe forma ynchronizaion synch., energy deecion, frequency offse compensaion FD (ar Frame Delimier) ignal daa rae of he payload (0A: 1 Mbi/s DBPK; 14: 2 Mbi/s DQPK) ervice fuure use, 00: complian Lengh lengh of he payload HEC (Header Error Check) proecion of signal, service and lengh, x 16 +x 12 +x variable bis synchronizaion FD signal service lengh HEC payload PLCP preamble PLCP header 4

5 MAC layer I - DFWMAC 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 PCF (Poin Coordinaion Funcion) Access mehods DFWMAC-DCF CMA/CA (mandaory) collision avoidance via randomized back-off mechanism minimum disance beween consecuive packes packe for acknowledgemens (no for broadcass) DFWMAC-DCF w/ RT/CT (opional) Disribued Foundaion Wireless MAC avoids hidden erminal problem DFWMAC- PCF (opional) access poin polls erminals according o a lis MAC layer II Prioriies defined hrough differen iner frame spaces no guaraneed, hard prioriies (hor Iner Frame pacing) highes prioriy, for, CT, polling response PIF (PCF IF) medium prioriy, for ime-bounded service using PCF (DCF, Disribued Coordinaion Funcion IF) lowes prioriy, for asynchronous daa service medium busy PIF conenion nex frame direc access if medium is free CMA/CA access mehod I aion ready o send sars sensing he medium (Carrier ense based on CCA, Clear Channel Assessmen) 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) medium busy direc access if medium is free nex frame slo ime (20µs) conenion window (randomized back-off mechanism) 5

6 compeing saions - simple version bo e bo r bo e bo r bo e busy saion 1 bo e busy saion 2 saion 3 busy bo e busy bo e bo r saion 4 bo e bo r bo e busy bo e bo r saion 5 busy medium no idle (frame, ack ec.) packe arrival a MAC bo e elapsed backoff ime bo r residual backoff ime CMA/CA access mehod II 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 sender receiver oher saions daa waiing ime conenion daa DFWMAC 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 RT daa CT oher saions NAV (RT) NAV (CT) defer access conenion daa 6

7 Fragmenaion RT frag sender 1 frag 2 CT receiver 1 2 oher saions NAV (RT) NAV (CT) NAV (frag 1 ) NAV ( 1 ) conenion daa DFWMAC-PCF I (almos never used) 0 1 uperframe medium busy PIF D poin 1 coordinaor wireless saions saions NAV NAV U 1 D2 U 2 DFWMAC-PCF II poin coordinaor wireless saions saions NAV D 3 NAV PIF D4 U 4 conenion free period CFend conenion period 7

8 Frame forma Types conrol frames, managemen frames, daa frames equence numbers imporan agains duplicaed frames due o los s Addresses receiver, ransmier (physical), B idenifier, sender (logical) Miscellaneous sending ime, checksum, frame conrol, daa byes Frame Duraion/ Address Address Address equence Address Daa CRC Conrol ID Conrol 4 bis Proocol version Type ubype To D From D More Frag Rery Power More WEP Mgm Daa Order MAC address forma D: Disribuion ysem AP: Access Poin DA: Desinaion Address A: ource Address BID: Basic ervice e Idenifier RA: Receiver Address TA: Transmier Address pecial Frames:, RT, CT Acknowledgemen Reques To end RT byes Frame Duraion Receiver Conrol Address CRC byes Frame Duraion Receiver Transmier CRC Conrol Address Address Clear To end byes Frame CT Duraion Receiver Conrol Address CRC 8

9 MAC managemen ynchronizaion ry o find a LAN, ry o say wihin a LAN synchronizaion of inernal clocks, generaion of beacons Power managemen sleep-mode wihou missing a message periodic sleep, frame buffering, raffic measuremens Associaion/Reassociaion inegraion ino a LAN roaming, i.e., change neworks by changing access poins scanning, i.e., acive search for a nework MIB - Managemen Informaion Base managing, read, wrie ynchronizaion using a Beacon (infrasrucure) beacon inerval (20ms 1s) access poin medium B B B B busy busy busy busy value of he imesamp B beacon frame ynchronizaion using a Beacon (ad-hoc) beacon inerval saion 1 B 1 B 1 saion 2 medium B 2 B 2 busy busy busy busy value of he imesamp B beacon frame random delay 9

10 Power managemen 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 Map (TIM) lis of unicas receivers ransmied by AP Delivery Traffic Indicaion Map (DTIM) lis of broadcas/mulicas receivers ransmied by AP Ad-hoc Ad-hoc Traffic Indicaion Map (ATIM) announcemen of receivers by saions buffering frames more complicaed - no cenral AP collision of ATIMs possible (scalabiliy?) APD (Auomaic Power ave Delivery) new mehod in e replacing above schemes Power saving wih wake-up paerns (infrasrucure) TIM inerval DTIM inerval access poin medium D B busy T T d D B busy busy busy saion T TIM D DTIM p awake d B broadcas/mulicas p P poll d daa ransmission o/from he saion Power saving wih wake-up paerns (adhoc) ATIM window beacon inerval saion 1 B 1 A D B 1 saion 2 B 2 B 2 a d B beacon frame random delay A ransmi ATIM D ransmi daa awake a acknowledge ATIM d acknowledge daa 10

11 Roaming No or bad connecion? Then perform: canning scan he environmen, i.e., lisen ino he medium for beacon signals or send probes ino he medium and wai for an answer Reassociaion Reques saion sends a reques o one or several AP(s) Reassociaion Response success: AP has answered, saion can now paricipae failure: coninue scanning AP 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 AP so i can release resources Fas roaming r e.g., for vehicle-o-roadside neworks WLAN: IEEE b Daa rae 1, 2, 5.5, 11 Mbi/s, depending on NR User daa rae max. approx. 6 Mbi/s Transmission range 300m oudoor, 30m indoor Max. daa rae ~10m indoor Frequency D, 2.4 GHz IM-band ecuriy Limied, WEP insecure, ID Availabiliy Many producs, many vendors Connecion se-up ime connecionless/always on Qualiy of ervice yp. bes effor, no guaranees (unless polling is used, limied suppor in producs) Manageabiliy limied (no auomaed key disribuion, sym. encrypion) pecial Advanages/Disadvanages advanage: many insalled sysems, lo of experience, available worldwide, free IM-band, many vendors, inegraed in lapops, simple sysem disadvanage: heavy inerference on IM-band, no service guaranees, slow relaive speed only IEEE b PHY frame formas Long PLCP PPDU forma variable bis synchronizaion FD signal service lengh HEC payload PLCP preamble PLCP header 192 µs a 1 Mbi/s DBPK 1, 2, 5.5 or 11 Mbi/s hor PLCP PPDU forma (opional) variable bis shor synch. FD signal service lengh HEC payload PLCP preamble (1 Mbi/s, DBPK) PLCP header (2 Mbi/s, DQPK) 96 µs 2, 5.5 or 11 Mbi/s 11

12 Channel selecion (non-overlapping) Europe (ETI) channel 1 channel 7 channel MHz [MHz] U (FCC)/Canada (IC) channel 1 channel 6 channel MHz [MHz] WLAN: IEEE a Daa rae 6, 9, 12, 18, 24, 36, 48, 54 Mbi/s, depending on NR User hroughpu (1500 bye packes): 5.3 (6), 18 (24), 24 (36), 32 (54) 6, 12, 24 Mbi/s mandaory Transmission range 100m oudoor, 10m indoor E.g., 54 Mbi/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 IM-band ecuriy Limied, WEP insecure, ID Availabiliy ome producs, some vendors Connecion se-up ime Connecionless/always on Qualiy of ervice Typ. bes effor, no guaranees (same as all producs) Manageabiliy Limied (no auomaed key disribuion, sym. Encrypion) pecial Advanages/Disadvanages Advanage: fis ino 802.x sandards, free IM-band, available, simple sysem, uses less crowded 5 GHz band Disadvanage: sronger shading due o higher frequency, no Qo IEEE a PHY frame forma variable 6 variable rae reserved lengh pariy ail service payload ail pad bis PLCP header PLCP preamble signal daa 12 1 variable symbols 6 Mbi/s 6, 9, 12, 18, 24, 36, 48, 54 Mbi/s 12

13 Operaing channels of a in Europe channel [MHz] 16.6 MHz channel MHz [MHz] cener frequency = *channel number [MHz] Operaing channels for a / U U-NII channel [MHz] 16.6 MHz channel cener frequency = *channel number [MHz] [MHz] 16.6 MHz OFDM in IEEE a OFDM wih 52 used subcarriers (64 in oal) 48 daa + 4 pilo (plus 12 virual subcarriers) khz spacing pilo khz channel cener frequency subcarrier number 13

14 WLAN: IEEE curren developmens (05/2008) c: Bridge uppor Definiion of MAC procedures o suppor bridges as exension o 802.1D d: Regulaory Domain Updae uppor of addiional regulaions relaed o channel selecion, hopping sequences e: MAC Enhancemens Qo Enhance he curren MAC o expand suppor for applicaions wih Qualiy of ervice requiremens, and in he capabiliies and efficiency of he proocol Definiion of a daa flow ( connecion ) wih parameers like rae, burs, period suppored by HCCA (HCF (Hybrid Coordinaor Funcion) Conrolled Channel Access, opional) Addiional energy saving mechanisms and more efficien reransmission EDCA (Enhanced Disribued Channel Access): high prioriy raffic wais less for channel access f: Iner-Access Poin Proocol (wihdrawn) Esablish an Iner-Access Poin Proocol for daa exchange via he disribuion sysem g: Daa Raes > 20 Mbi/s a 2.4 GHz; 54 Mbi/s, OFDM uccessful successor of b, performance loss during mixed operaion wih.11b h: pecrum Managed a Exension for operaion of a in Europe by mechanisms like channel measuremen for dynamic channel selecion (DF, Dynamic Frequency elecion) and power conrol (TPC, Transmi Power Conrol) i: Enhanced ecuriy Mechanisms Enhance he curren MAC o provide improvemens in securiy. TKIP enhances he insecure WEP, bu remains compaible o older WEP sysems AE provides a secure encrypion mehod and is based on new hardware WLAN: IEEE curren developmens (05/2008) j: Exensions for operaions in Japan Changes of a for operaion a 5GHz in Japan using only half he channel widh a larger range : Curren complee sandard Comprises amendmens a, b, d, e, g, h, i, j k: Mehods for channel measuremens Devices and access poins should be able o esimae channel qualiy in order o be able o choose a beer access poin of channel m: Updaes of he sandard n: Higher daa raes above 100Mbi/s Changes of PHY and MAC wih he goal of 100Mbi/s a MAC AP MIMO anennas (Muliple Inpu Muliple Oupu), up o 600Mbi/s are currenly feasible However, sill a large overhead due o proocol headers and inefficien mechanisms p: Iner car communicaions Communicaion beween cars/road side and cars/cars Planned for relaive speeds of min. 200km/h and ranges over 1000m Usage of GHz band in Norh America r: Faser Handover beween B ecure, fas handover of a saion from one AP o anoher wihin an E Curren mechanisms (even newer sandards like i) plus incompaible devices from differen vendors are massive problems for he use of, e.g., VoIP in WLANs Handover should be feasible wihin 50ms in order o suppor mulimedia applicaions efficienly WLAN: IEEE curren developmens (05/2008) s: Mesh Neworking Design of a self-configuring Wireless Disribuion ysem (WD) based on uppor of poin-o-poin and broadcas communicaion across several hops T: Performance evaluaion of neworks andardizaion of performance measuremen schemes u: Inerworking wih addiional exernal neworks v: Nework managemen Exensions of curren managemen funcions, channel measuremens Definiion of a unified inerface w: ecuring of nework conrol Classical sandards like , bu also i proec only daa frames, no he conrol frames. Thus, his sandard should exend i in a way ha, e.g., no conrol frames can be forged y: Exensions for he MHz band in he UA z: Exension o direc link seup Noe: No all sandards will end in producs, many ideas ge suck a working group level Info: 802wirelessworld.com, sandards.ieee.org/ geieee802/ 14

15 Blueooh Blueooh Basic idea Universal radio inerface for ad-hoc wireless conneciviy Inerconnecing compuer and peripherals, handheld devices, PDAs, cell phones replacemen of IrDA Embedded in oher devices, very cheap hor range (10 m), low power consumpion, license-free 2.45 GHz IM Voice and daa ransmission, approx. 1 Mbi/s daa rae One of he firs modules (Ericsson). Blueooh (was: ) Hisory 1994: Ericsson (Maison/Haarsen), MC-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, : erecion of a rune sone a Ercisson/Lund 2001: firs consumer producs for mass marke, spec. version 1.1 released 2005: 5 million chips/week pecial Ineres Group Original founding members: Ericsson, Inel, IBM, Nokia, Toshiba Added promoers: 3Com, Agere (was: Lucen), Microsof, Moorola > members Common specificaion and cerificaion of producs 15

16 Hisory and hi-ech and he real rune sone 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. 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 ) This could be he original colors of he sone. Characerisics 2.4 GHz IM band, 79 RF channels, 1 MHz carrier spacing Channel 0: 2402 MHz channel 78: 2480 MHz 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, poin-o-poin, circui swiched Daa link ACL (Asynchronous ConnecionLess) Asynchronous, acknowledgmens, 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 16

17 Picone 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 Maser deermines hopping paern, slaves have o synchronize B P M P Each picone has a unique hopping paern P B Paricipaion in a picone = synchronizaion o hopping sequence Each picone has one maser and up o 7 simulaneous slaves (> 200 could be parked) M=Maser =lave P=Parked B=andby Forming a picone All devices in a picone hop ogeher Maser gives slaves is clock and device ID Hopping paern: deermined by device ID (48 bi, unique worldwide) Phase in hopping paern deermined by clock Addressing Acive Member Address (AMA, 3 bi) Parked Member Address (PMA, 8 bi) P B B M P B B B B B B B B P B 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 M=Maser =lave P=Parked B=andby B P P M B P M B P Picones (each wih a capaciy of 720 kbi/s) 17

18 Frequency selecion during daa ransmission 625 µs f k f k+1 f k+2 f k+3 f k+4 f k+5 f k+6 M M M M f k f k+3 f k+4 f k+5 f k+6 M M M f k f k+1 f k+6 M M Baseband Picone/channel definiion Low-level packe definiion Access code Channel, device access, e.g., derived from maser Packe header acive member address (broadcas + 7 slaves), link ype, alernaing bi ARQ/EQ, checksum 68(72) bis access code packe header payload 4 64 (4) bis preamble sync. (railer) AM address ype flow ARQN EQN HEC CO payload ypes payload (30) HV1 audio (10) FEC (20) HV2 audio (20) FEC (10) HV3 audio (30) DV audio (10) Header (1) Payload (0-9) 2/3 FEC CRC (2) 18

19 ACL Payload ypes payload (0-343) header (1/2) payload (0-339) CRC (2) DM1 header (1) payload (0-17) 2/3 FEC CRC (2) DH1 header (1) payload (0-27) CRC (2) (byes) DM3 DH3 header (2) payload (0-121) 2/3 FEC header (2) payload (0-183) CRC (2) CRC (2) DM5 DH5 header (2) payload (0-224) 2/3 FEC header (2) payload (0-339) CRC (2) CRC (2) AUX1 header (1) payload (0-29) Baseband link ypes Polling-based TDD packe ransmission 625µs slos, maser polls slaves CO (ynchronous Connecion Oriened) Voice Periodic single slo packe assignmen, 64 kbi/s full-duplex, poin-o-poin ACL (Asynchronous ConnecionLess) Daa Variable packe size (1, 3, 5 slos), asymmeric bandwidh, poin-omulipoin MATER CO ACL CO ACL CO ACL CO ACL f 0 f 4 f 6 f 8 f 12 f 14 f 18 f 20 LAVE 1 f 1 f 7 f 9 f 13 f 19 LAVE 2 f 5 f 17 f 21 Robusness low frequency hopping wih hopping paerns deermined by a maser Proecion from inerference on cerain frequencies eparaion from oher picones (FH-CDMA) Reransmission ACL only, very fas Forward Error Correcion CO and ACL Error in payload (no header!) NAK MATER A C C F H LAVE 1 B D E LAVE 2 G G 19

20 Baseband saes of a Blueooh device sandby unconneced deach inquiry page connecing ransmi AMA conneced AMA acive park PMA hold AMA sniff AMA low power andby: do nohing Inquire: search for oher devices Page: connec o a specific device Conneced: paricipae in a picone Park: release AMA, ge PMA niff: lisen periodically, no each slo Hold: sop ACL, CO sill possible, possibly paricipae in anoher picone Blueooh versions Blueooh 1.1 also IEEE andard iniial sable commercial sandard Blueooh 1.2 also IEEE andard eco (exended CO): higher, variable biraes, reransmission for CO AFH (adapive frequency hopping) o avoid inerference Blueooh EDR (2004, no more IEEE) EDR (enhanced dae rae) of 3.0 Mbi/s for ACL and eco lower power consumpion due o shorer duy cycle Blueooh EDR (2007) beer pairing suppor, e.g., using NFC improved securiy WPAN: IEEE Blueooh Daa rae ynchronous, connecionoriened: 64 kbi/s Asynchronous, connecionless kbi/s symmeric / 57.6 kbi/s asymmeric Transmission range PO (Personal Operaing pace) up o 10 m wih special ransceivers up o 100 m Frequency Free 2.4 GHz IM-band ecuriy Challenge/response, hopping sequence Availabiliy Inegraed ino many producs, several vendors Connecion se-up ime Depends on power-mode Max. 2.56s, avg. 0.64s Qualiy of ervice Guaranees, ARQ/FEC Manageabiliy Public/privae keys needed, key managemen no specified, simple sysem inegraion pecial Advanages/ Disadvanages Advanage: already inegraed ino several producs, available worldwide, free IM-band, several vendors, simple sysem, simple ad-hoc neworking, peer o peer, scaernes Disadvanage: inerference on IM-band, limied range, max. 8 acive devices/nework, high seup laency 20

21 WPAN: IEEE fuure developmens : Coexisence Coexisence of Wireless Personal Area Neworks (802.15) and Wireless Local Area Neworks (802.11), quanify he muual inerference : High-Rae andard for high-rae (20Mbi/s or greaer) WPANs, while sill low-power/low-cos Daa Raes: 11, 22, 33, 44, 55 Mbi/s Qualiy of ervice Ad hoc peer-o-peer neworking ecuriy Low power and low cos Designed o mee he demanding requiremens of porable consumer imaging and mulimedia applicaions WPAN: IEEE fuure developmens 2 everal working groups exend he sandard a: - wihdrawn - Alernaive PHY wih higher daa rae as exension o Applicaions: mulimedia, picure ransmission b: Enhanced ineroperabiliy of MAC Correcion of errors and ambiguiies in he sandard c: Alernaive PHY a GHz Goal: daa raes above 2 Gbi/s No all hese working groups really creae a sandard, no all sandards will be found in producs laer WPAN: IEEE fuure developmens : Low-Rae, Very Low-Power Low daa rae soluion wih muli-monh o muli-year baery life and very low complexiy Poenial applicaions are sensors, ineracive oys, smar badges, remoe conrols, and home auomaion Daa raes of kbi/s, laency down o 15 ms Maser-lave or Peer-o-Peer operaion Up o 254 devices or simpler nodes uppor for criical laency devices, such as joysicks CMA/CA channel access (daa cenric), sloed (beacon), unsloed Auomaic nework esablishmen by he PAN coordinaor Dynamic device addressing, flexible addressing forma Fully handshaked proocol for ransfer reliabiliy Power managemen o ensure low power consumpion 16 channels in he 2.4 GHz IM band, 10 channels in he 915 MHz U IM band and one channel in he European 868 MHz band Basis of he ZigBee echnology 21

22 ZigBee Relaion o similar o Blueooh / Pushed by Chipcon (now TI), Ember, Freescale (Moorola), Honeywell, Misubishi, Moorola, Philips, amsung More han 260 members abou 15 promoers, 133 paricipans, 111 adopers mus be member o commercially use ZigBee spec ZigBee plaforms comprise IEEE for layers 1 and 2 ZigBee proocol sack up o he applicaions WPAN: IEEE fuure developmens a: Alernaive PHY wih lower daa rae as exension o Properies: precise localizaion (< 1m precision), exremely low power consumpion, longer range b, c, d: Exensions, correcions, and clarificaions regarding Usage of new bands, more flexible securiy mechanisms : Mesh Neworking Parial meshes, full meshes Range exension, more robusness, longer baery live : Body Area Neworks Low power neworks e.g. for medical or enerainmen use No all hese working groups really creae a sandard, no all sandards will be found in producs laer ome more IEEE sandards for mobile communicaions IEEE : Broadband Wireless Access / WirelessMAN / WiMax Wireless disribuion sysem, e.g., for he las mile, alernaive o DL 75 Mbi/s up o 50 km LO, up o 10 km NLO; 2-66 GHz band Iniial sandards wihou roaming or mobiliy suppor e adds mobiliy suppor, allows for roaming a 150 km/h IEEE : Mobile Broadband Wireless Access (MBWA) Licensed bands < 3.5 GHz, opimized for IP raffic Peak rae > 1 Mbi/s per user Differen mobiliy classes up o 250 km/h and ranges up o 15 km Relaion o e unclear IEEE : Media Independen Handover Ineroperabiliy andardize handover beween differen 802.x and/or non 802 neworks IEEE : Wireless Regional Area Neworks (WRAN) Radio-based PHY/MAC for use by license-exemp devices on a noninerfering basis in specrum ha is allocaed o he TV Broadcas ervice 22

23 IM band inerference Many sources of inerference Microwave ovens, microwave lighing , b, g, , Even analog TV ransmission, surveillance Unlicensed meropolian area neworks Levels of inerference Physical layer: inerference acs like noise pread specrum ries o minimize his FEC/inerleaving ries o correc MAC layer: algorihms no harmonized E.g., Blueooh migh confuse vs /Blueooh Blueooh may ac like a rogue member of he nework f [MHz] Does no know anyhing abou gaps, iner frame spacing ec b bye 100 bye 1000 bye 100 bye 500 bye 100 bye 3 channels (separaed by insallaion) IEEE discusses hese problems Proposal: Adapive Frequency Hopping a non-collaboraive Coexisence Mechanism Real effecs? Many 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 channels (separaed by hopping paern) 23