2eb10b18fa Are you looking for. Muhamed, Fundamentals of WIMAX 46Wireless Systems From Narrowband to Broadband 47What do service providers need?Highest possible consumer satisfaction QoS is primary requirement video and high throughput (mobile) data sessions Management capability to the devices easy service provisioning, billing. Wide availability of terminal devices 802.11n MIMO techniques for range extension and higher bit rates 54Wireless LAN Standards802.11b (Current Generation) Standard for 2.4GHz ISM band (80 MHz) Frequency hopped spread spectrum 1.6-10 Mbps, 500 ft range 802.11a (Emerging Generation) Standard for 5GHz NII band (300 MHz) OFDM with time division 20-70 Mbps, variable range Similar to HiperLAN in Europe 802.11g (New Standard) Standard in 2.4 GHz and 5 GHz bands OFDM Speeds up to 54 Mbps 55IEEE 802.11nOver-the-air (OTA) 200 Mbps MAC layer 100Mbps Rich content distribution- 3 HDTV quality streams and simultaneous broadband access VoIP over WLAN supporting many simultaneous clients Service providers microcells, neighborhood area networks (NANs) PHY MIMO/multiple antenna techniques Advanced FEC, (forward error correction) 10, 20 40Mhz channels widths Higher order modulation/coding MAC Flexible efficient packet aggregation Legacy and channel width coexistence Power saving mechanisms Novel data flow techniques 56WLAN Network ArchitectureBasic Service Set (BSS) a set of stations which communicate with one anotherInfrastructure ModeAd hoc network Only direct communication possible No relay function Stations communicate with AP AP provides connection to wired network (e.g. Write a Comment . Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free. About This Presentation . (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE.. Its MAC scheme CSMA (Carrier Sense Multiple Access) is inefficient for large numbers of users The interference constraints of operating in the license-exempt band is likely to significantly reduce the actual capacity of outdoor Wi-Fi systems.
Wi-Fi systems are not designed to support high-speed mobility. Broadband internet access is also growing rapidly 31Sept 2006 figures 2.53 Billion total 2.02 B (GSM), 320 M (CDMA), 81.2M UMTS Source http//www.3gamericas.org/English/Statistics/ 32WLAN Market WiFiWLAN Growth Drivers Convenience Flexibility Productivity Gains Low Cost Embedded WLANSource AirTight Networks 33Wireless The Big Picture 34Wireless Understanding the Big PictureWireless (vs wired) communication medium Cellular (vs meshed vs MANETs) architectures for coverage, capacity, QoS, mobility, auto-configuration, infrastructure support Mobile (vs fixed vs portable) implications for devices phone vs PSP vs PDA vs laptop vs ultramobile WAN (vs WLAN vs WMAN) network scope, coverage, mobility Market segments Home networks, SOHO, SME, enterprise, Hotspots, WISPs, cellular Technologies/Standards/Marketing Alliances 802.11, UWB, Bluetooth, Zigbee, 3G, GSM, CDMA, OFDM, MIMO, Wimax 35Mobile Computing/Entertainment/CommnsiPoD impact of disk size/costSamsung Cameraphone w/ camcorderComputing smaller, faster Disks larger size, small form Communications wireless voice, data Multimedia integration voice, data, video, gamesSONY PSP mobile gaming Blackberry phone PDA 36Variety of Wireless-Capable Devices 2006 Thanksgiving sales lt 1000 Plasma 42 TVs. User Comments (0) . Collisions when multiple piconets nearby. 403 Forbidden.. Or use it to upload your own PowerPoint slides so you can share them with your teachers, class, students, bosses, employees, customers, potential investors or the world. 1992 - Start of GSM In Germany as D1 and D2, fully digital, 900MHz, 124 channels Automatic location, hand-over, cellular Roaming in Europe - now worldwide in more than 170 countries Services data with 9.6kbit/s, FAX, voice, . Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free. historical buildings, fire protection, esthetics) Robust against disasters like earthquake, fire and careless users which remove connectors! Disadvantages Generally very low transmission rates for higher numbers of users Often proprietary, more powerful approaches, standards are often restricted Many national regulations, global regulations are evolving slowly Restricted frequency range, interferences of frequencies Nevertheless, in the last 10-20 years, it has really been a wireless revolution 29The Wireless RevolutionCellular is the fastest growing sector of communication industry (exponential growth since 1982, with over 2 billion users worldwide today) Three generations of wireless First Generation (1G) Analog 25 or 30 KHz FM, voice only, mostly vehicular communication Second Generation (2G) Narrowband TDMA and CDMA, voice and low bit-rate data, portable units.
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