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1、September 8, 2003Technology Directions for 802.11 WLANUbiquitous Wireless BroadbandCraig Barratt, Ph.D., President & CEOAtheros Communications, Inc. 2Atheros OverviewInnovator in 802.11a, a/b, b/g, and a/b/g chipsetsnBest clients for range and throughput according to publication reviewsnUniversal w
2、ireless access with dual band, multimode productsOver 200 Atheros-based products on market worldwidenLeading laptop and retail vendors use embedded multimode WLAN from AtherosnAdvanced security with AES,CCX,WPA; certified international operation; Quality of ServiceFirst digitalCMOS OFDMradios - 1999
3、First 802.11achipsets - 2001First Wi-Fi audio/videoproducts - 2001First DSRCautomotiveapplications - 2002First 802.11a/bchipsets - 2002First certified 802.11a/b/gand b/g chipsets - 2003First wireless as fast aswired (Super G) - 2003 3Some of Our Customers 4Proliferation of WLAN and OFDM 3rd Gen OFDM
4、 802.11a802.11a/b802.11a/g/b designsThe availability of low cost, robust, standards-based WLAN products will influence the home entertainment, public access, and telematics markets enormously.ConsumerElectronicsWLANHot SpotsVehicularApplications 5WLAN in Consumer ElectronicsnPortable devices (Camera
5、, Camcorder, Mobile Tablet, Laptop)nBattery powered low power consumptionnSmall small form factornSingle room range feasible and sufficientnFixed devices (Set top box, TV, DVD, Media Center)nLine powered can have higher power assumptionnLarger larger form factornWhole house range feasible and desire
6、dSatellite, Cable, DSL ConnectionSTB/HomeGatewayTVsStereosPCsCamcorder 6Wireless LAN Hot SpotsHot Spot growth now driven internationally by telecom carriersGreatest growth in Japan with NTT aggressively rolling out 802.11a and 802.11b dual mode access points and expanding WLAN to4.9 GHzSource: IDC,C
7、orp. Reports 7802.11 Technology Comparison802.11802.11b802.11g802.11aStandard ApprovedJuly 1997Sept 1999June, 2003Sept 1999Available Spectrum83.5MHz83.5MHz83.5MHz125MHzFrequencies of Operation in China2.400-2.4835GHz2.400-2.4835GHz2.400-2.4835GHz5.725-5.85GHzNon-Overlapping Channels333513-24 (US)Mod
8、ulation TechnologyFHSSDSSSCCKCCK,OFDMOFDMData Rate per Channel1, 21, 2, 5.5, 111, 2, 5.5, 6, 9, 11, 12, 18,24, 36, 48, 546, 9, 12, 18,24, 36, 48, 54Max UDP Throughput(1500 byte)1.7 Mbps7.1 Mbps19.5 Mbps*30.7 MbpsMax TCP/IP Throughput (1500 byte)1.6 Mbps5.9 Mbps14.4 Mbps*24.0 Mbps* With any 802.11b s
9、tation in the network, CTS-only mode. 8Important IEEE Working Groups802.11e Quality of ServicenEDCF parameterized QoS and HCF polling-based QoS802.11i SecuritynRobust Secure Network: (1) AES Encryption, (2) EAP Authentication802.11h DFS/TPCnRadar detection and avoidance for European operation802.11f
10、 Inter-Access Point ProtocolnCommunication between APs for roaming and handover802.11k Radio Resource ManagementnImproved physical layer management and reporting802.11n High Throughput WLANnExtending WLAN data rates beyond 108 Mbps 9The Advent of Multimode 802.11a/b/gThe Standards Battles are OvernU
11、niversal connectivity is the watchword of the daynComprehensive protocol supportnWorldwide tuning range, 2.3 2.5 GHz, 4.9 5.9 GHznLine-speed AES and WPA encryption for fast, secure connectionsnParadigm-shift enhancements to range and throughputnCost reduction curve unprecedented in wireless communic
12、ations 10Evolution in the Wi-Fi Market802.11b has become a legacy market with almost all new products coming to market with multimode b/g and a/b/g802.11bb/ga/b/gPC OEMb/ga/b/gRetail 11Toward a Secure Wireless NetworkIndustry Convergence on AES Encryption and EAP AuthenticationnEncryption standards
13、have progressed from WEP, to TKIP, and finally to AESnAuthentication protocols have progressed from 802.1x, to EAP, to vendor-specific implementations such as LEAP and PEAPnWi-Fi Protected Access (WPA) is the current state-of-the-art. WPA mandates TKIP encryption and EAP authentication. WPA2 upgrade
14、s encryption to AES.nClosely monitoring Chinese standards GB15629.11 and GB15629.1102 for WAPI compliance 12Throughput and Range EnhancementsExtends the Efficiency and Reach of Wireless ConnectionsLarge frames, compression, and packet bursting dramatically improve throughput -100 dBm Receive Sensiti
15、vity is close to cellular, 20 dB better than Wi-Fi spec Delivers Seamless InteroperabilityFully interoperable with standard 802.11a, 802.11b, and 802.11g trafficLine-of-SightRange(meters)Standard 11gAtheros Range Extended 11a/g790mFor Offices:Eliminates Dead SpotsFor Homes:Single-AP CoverageFor Publ
16、ic Access:Cover Larger Areas 13Whither WLAN?802.11DataThroughput3G90Mbps1Mbps 100m 500m Range (Indoor) 802.11 with Range ExtensionWireless LAN and cellular have traditionallyhad different applications and usage models Local area network ( 500 m) 14The Shape of WLAN ConvergenceCordlessCordless(DECT,
17、CT-2)CellularCellular(GSM, CDMA)WLANWLAN(802.11 a/b/g)?VoiceDataLocal AreaWide Area 15Technology Comparison: 802.11 & 3G802.11a/g3GScope of StandardL1, L2Voice/DataL1 L7Voice/DataAvailable Spectrum in China200+ MHz175 MHzSupported Data Rates6-54 Mbps384 kbps - 2 MbpsChannel Bandwidth20 MHz5 MHzSpect
18、ral Efficiency (Maximum)2.7 bps/Hz0.4 bps/HzCoverage Range (Radius)100m - 1 km2-3 kmSystem Capacity/Cell (Maximum)54 Mbps x km218 Mbps x km2Infrastructure Cost/CellRMB 20,000RMB 2,000,000Terminal CostRMB 400RMB 4,000 16WLAN Moves Beyond “Local”Toward Long-Range, Metropolitan-Area Coveragen12 km poin
19、t-to-point links 36 Mbps have been demonstratednRequires increased transmit power, antenna directionalitynProtocol modifications are also possible Far terminal, 12.5 km awayPhotos courtesy of Microelectronics Technology, Inc. 17WLAN Implications for ChinaWi-Fi Is a True Telecommunications Technology
20、 HerenCan deliver ubiquitous broadband coverage, at commodity prices802.11802.11 802.11802.11 or 802.16IndustrialMetropolitanResidential 18SummaryWi-Fi Combines the Best of Datacom and Telecomn802.11 chipsets implemented in CMOS leverage Moores LawnLarge amounts of unlicensed spectrum lower costs fu
21、rthernWi-Fi is wireless Ethernet (IP-based)nL1, L2 orientation fosters openness and innovation at higher layersnATM, Token Ring, Frame Relay, FDDI, and other hierarchical protocols have competed against Ethernet/IP and lostnIP is now a core telecommunications technologynClosing advice: dont bet against (wireless) Ethernet!谢 谢! 19
