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Wi-Fi

Wi-Fi. 08. 02. 2011 Hyunshik Seo. CONTENTS What is Wi-Fi ? A short history of Wi-Fi How Wi-Fi works Internet access technology Topology of Wi-Fi Location-aware applications based on Wi-Fi. 2. What is Wi-Fi ? The name Wi-Fi Suggests Wireless Fidelity

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Wi-Fi

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  1. Wi-Fi 08. 02. 2011 HyunshikSeo

  2. CONTENTS • What is Wi-Fi ? • A shorthistory of Wi-Fi • HowWi-Fiworks • Internet accesstechnology • Topology of Wi-Fi • Location-awareapplicationsbased on Wi-Fi 2

  3. What is Wi-Fi ? • The name Wi-Fi • Suggests Wireless Fidelity • A trademark of the Wi-Fi Alliance • used to describe the underlying technology of wireless local area networks (WLAN) based on the IEEE 802.11 specifications • Initially, Wi-Fi was used in place of only the 2.4GHz 802.11b standard • Expanded the use of term to include 802.11a, 802.11b, 802.11g, and so on • IEEE 802.11a: high speed extension to the 5GHz band • IEEE 802.11b/g: high speed extension to the 2.4GHz band 3

  4. What is Wi-Fi ? • Basics of Wi-Fi • Popular wireless networking technology • Enable devices such as computer or smartphone can connect to the internet • Works with radio waves through space • basedon access point (AP) which broadcasts a wireless signal 4

  5. A short history of Wi-Fi • 1985 – Federal Communications Commission (FCC) opens up “garbage bands” for communication purposes without need for government licenses • 1988 – Institute of Electrical and Electronics Engineers (IEEE) setup a committee called 802.3 and defined Ethernet standard (later setup 802.11 committee) • 1999/2000 – 802.11b and 802.11a standards were ratified • Wireless Ethernet Compatibility Alliance (WECA) formed by Intersil, 3Com, Nokia, Aironet, and Lucent • 1999 – Apple computers teamed with Lucent to add wireless slot to all laptops 5

  6. How Wi-Fi works • Internet accesstechnology • Connection between devices and internet • Wi-Fi devices needs to be within range of a wireless network or an internet hot spot where wireless access to the internet is available • Wireless internet access is availablewithaccess point which could be either wireless orwireddevice 6

  7. How Wi-Fi works • Topology of a Wi-Fi • Point-to-point • Usually very high speed and high capacity • can be used to extend a net-work over great distances • Requires a clear line of sight to tower 7

  8. How Wi-Fi works • Point-to-multipoint • Similar technology to point-to-point network • more than one device communicates with a central point Omnidirectionalantenna 8

  9. How Wi-Fi works • Multipoint-to-multipoint • Distributed gateway dev-ices • Self healing network • known as an ad-hoc or mesh network 9

  10. Location-awareapplicationsbased on Wi-Fi (1) • Wi-Fi positioning system (WPS) • Based on wireless fidelity network • Uses information from APs around and from data- base through Wi-Fi to determine position 10

  11. Location-awareapplicationsbased on Wi-Fi • Technologies in WPS • Getting wireless information from APs (such as MAC address, channel, signal strength, noise strength and so on) • Storing the APs’ locations in database, which are estimated from the obtained information from the APs • Gathering some information from mobile device • Making a determination of user’s position by comparing informat- ion from database and from mobile device 11

  12. Location-awareapplicationsbased on Wi-Fi • Comparisonwith GPS • Relatively cheap • Availability in indoors • e.g. inside a building • High accuracy • GPS only determines the location of object within a few hun-dred meters but Wi-Fi can give a location within 20 to 30 me-ters • However, it depends on the density of Wi-Fi signals or the number of routers 12

  13. Location-awareapplicationsbased on Wi-Fi • WiFiLocation Services • SkyhookWiFiLocation Service API (Launched in 2003) • NavizonWiFiLocation Service API (Launched in 2005) • Verizon Wireless WiFi Location Service API (Launched in 2010) • Google WiFiLocation Service API (Launched in 2008) • Apple iPhoneWiFiLocation Service API (Launched in 2010, Wi-FiFinder) 13

  14. Location-awareapplicationsbased on Wi-Fi • Wi-FiFinder for iPhone • Indoor and outdoor route finding • Find Wi-Fi hotspots near you • Search for public Wi-Fi anywhere in the world 14

  15. Location-awareapplicationsbased on Wi-Fi (2) • Wireless campus LBS • Project at the University of Twente (UT) in cooperation with companies • Based on technology and applications of wireless and mobile communication 15

  16. Location-awareapplicationsbased on Wi-Fi • Features are • Mobile guide to find route both in and out of building • Mobile guide to find books in library • Mobile guide to find friends 16

  17. Location-awareapplicationsbased on Wi-Fi (3) • The Cisco Location-Aware Healthcare system • To maintain many patients and staffs in hospital • based on Wi-Fi Location System • Features are • Monitoring of patient location • Optimizing workflow and staff management 17

  18. THANK YOU  18

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